STK 4050 200WATT POWER AMPLIFIER CIRCUIT DIAGRAM

 

Amplifier circuit with IC STK is tough and good quality. In this article an amplifier circuit with IC STK another base. Power "Amplifier 200Watt By STK4050" is an audio amplifier of the STK family with 200Watt power. To create a power amplifier with the STK4050 IC is not require many external components.

Power Amplifier uses symmetric 30Volt power supply system. Power Amplifier With this STK4050 can reproduce the power 200 Watts at 8 Ohm load spaker. In making Power Amplifier 200Watt With this STK4050 do not forget to provide adequate heat sink for the IC STK 4050 in order to avoid overheating.

Schematics Amplifier STK4050-STK4046

PCB Layout Amplifier

Series Power Supply for Power Amplifier 200Watt By STK4050 been displayed in one image with a series of "Power Amplifier" 200Watt With STK4050 above. IC STK 4050 in this series there are several types on the market including STK4050II, STK4050V and STK4050.

And below is a list of STK ICs are used for a good quality amplifier.

Datasheet STK IC Amplifier

SIMPLE LED WORKBENCH LIGHTING CIRCUIT DIAGRAM

 Here is a very useful workbench lighting unit for electronics hobbyists. The portable inspection lamp circuit consists of an on-board voltage regulator and a high-bright 5mm white LED. Any 9 to 18 volt dc rated ac mains adaptor, capable to source about 100 mA of output current can be used to power this portable inspection lamp.

After construction the led workbench light circuit should be enclosed in a suitable plastic bottle cap as illustrated here. The miniature lens shown is an optional component. In the prototype, plastic made lens lifted from a discarded torch was used!

LED workbench lighting lamp circuit schematic

The adjustable 3-pin voltage regulator IC1 (LM317L) in TO-92 pack, is here tuned to supply an output of near 4.5 volt dc. This supply is directly fed to the white LED (D2) through the current limiter resistor R3 (51 Ohm). Diode D1 (1N4001) works as an input polarity protection guard and two small electrolytic capacitors (C1 and C2) connected at the input and output pins of IC1 improves the overall stability of the regulator circuit. Use a standard RCA or EP socket as the input terminal J1.

AUTOMATIC FAN CONTROLLER CIRCUIT DIAGRAM

 

Pc/power supply  fan is one of the most crucial components to ensure the smooth running of your computer. But often or not, many of us get annoyed because of the resultant noise.and very good overall functionality that makes it a perfect choice for very demanding users.

 

This circuit will turn on/off 12V DC fan or CPU fan when temperature above normal temperature.You can set turn on temperature by adjust VR1. This circuit use an NTC (Negative temperature coefficient)which is a thermistor is one in which the zero-power resistance decreases with an increase in temperature. So If temperature increate the voltage at pin 3 on LM311 will decreated .The resistance of NTC is about 10K at 25'c.

VR1 should be multi-turn potentiometer type such 10K/25 turn link

12V 50W SWITCHING REGULATOR CIRCUIT SCHEMATIC DIAGRAM

 By definition, a switch mode power supply (SMPS) is a type of power supply that uses semiconductor switching techniques, rather than standard linear methods to provide the required output voltage. The basic switching converter consists of a power switching stage and a control circuit.

 
The schematic diagram below shows a simple trivial low-cost 12 volt DC 50W off-line SMPS switching power supply circuit. It can be used for DIY home projects or to learn operation of flyback converters. This PSU can work over a universal input AC line range 90-264 VAC. It provides a nominal 12V DC output at more than 4A load. Line and load regulation is better then 0.5%.
The unit has over current, over temperature and over voltage protections, as well as passive inrush current limiting. Output ripple are approximately 0.2 V peak to peak in the range 0 to 20 MHz. If you need to get lower ripple, you may put an additional output capacitor or an LC filter outside of the feedback loop. This project is a modification of a 24V circuit that I've designed many years ago as a consultant for a small company. That company wanted a plug-in replacement to a cheap off-the-shelf AC to DC power supply, which had a long lead time. By the time I've completed the design and built a proto, they found the off-the-shelf part elsewhere in stock. So, they never proceeded with a manufacturing of this module. Accordingly, I have not tested this design beyond a basic DVT. You can build this circuit for personal use (at your own risk of course). But you are not allowed to republish the content of this page anywhere or use it for commercial purposes without my permission.

SAFETY WARNING.
 
To safely test or troubleshoot this circuit it is recommended to power it via an isolation transformer or from an isolated AC source. Also note that an offline single-transistor flyback converter generates internal voltages which may reach 600 V. Don't try to play with this circuit unless you are of a legal age, understand power electronics and know how to deal safely with high voltage. You may want to take our quick power supply safety quiz.

CIRCUIT OPERATION.

This AC to DC power supply utilizes a fly back, which is the simplest SMPS converter topology. It uses an 800V/11A MOSFET (Q1) as the switching device and PWM controller UC3844AN (U3). The input section includes a fuse, EMI filter, inrush current limiting NTC resistor R1, a full bridge rectifier CR1, and a DC bus filter capacitor C2.

The initial start-up current for the PWM IC is provided by "bleeding" resistors R7, R8 that allow small current which charges the Vcc capacitor C7.

When the Vcc pin of U3 reaches the positive under voltage lockout threshold (typically 14V-16V), the IC starts to operate and will be driving ON and OFF the switch Q1 via a gate drive resistor R4 at a fixed frequency (in this circuit it is 100 kHz). When Q1 turns on, the DC bus voltage is applied across the transformer T1 primary winding, current through the transformer primary ramps up and energy is accumulated in the transformer's magnetic field. Diodes D4 and D7 during this time interval are reversed biased. When Q1 turns off, the energy stored in the magnetic field causes the voltages across all winding to reverse polarity. As a result, output rectifiers D4 and D7 conduct and the stored energy is transferred to the output and to the bias circuit.Once the converter is started, the bias for the control PWM comes from the bias winding of the transformer.

The secondary side feedback control loop uses a TL431 precision shunt regulator D1 as both the reference and an error amplifier. It compares divided output voltage to D1's internal reference 2.5V. An optocoupler U1 feeds the current proportional to the error signal across the transformer galvanic isolation boundary back to the primary PWM. If accurate regulation of the output is not required, the feedback can be taken from the bias voltage at C9 and fed via a divider into feedback pin 2.

Primary current in T1 is sensed by a resistor R6. This current sense voltage is applied through a spike filter to the current sense terminal of U3, where it is compared against the scaled down error signal at compensation pin 1. When current sense voltage ramp reaches 1/3×(Vpin1-1), the pulse is terminated and Q1 turns off.
Zener diode D6 with optocoupler U2 provide a non-latching output's overvoltage protection.

Thermal switch shuts down the power supply when temperature on the MOSFET heatsink exceeds 95-100 oC.

Here is complete BOM. Note that it was compiled more than ten years ago. Some part numbers may need replacements.

Printed Circuit Boards:

The transformer design may look unusual. Note that a flyback transformer operates as an inductor: it accumulates energy in the magnetic field during ON period of Q1. Then it transfers it (minus losses) into the secondaries during the OFF period of Q1. In order to store energy efficiently with minimal physical size, a non-magnetic gap is needed in series with a high permeability magnetic core material. Flyback transformer design usually uses ferrite cores with a physical gap, or powdered metal cores with an inherently present distributed gap. Gapped ferrites normally feature lower losses, but they have abrupt saturation curve. Powder cores have higher losses, but their B(H) curve is soft. Among other form factors, toroidal transformers have lowest leakage inductance. In this PSU the transformer is made with KoolM powder toroidal core. Proper winding phasing is critical in flybacks just like in all single-ended converters. If windings are misphased the circuit will not work or may simply blow up. Refer to the schematic and winding diagram above for proper transformer installation. All coils in this design have to be made of wire with two or more layers of Teflon insulation to assure reinforced insulation between primary and secondary.

TEMPERATURE INDICATOR SCHEMATIC CIRCUIT DIAGRAM

  In this temperature indicator, diode voltage drop in ambient temperature is used as reference level. Temperature is measured by a transistor mounted on a radiator or near power transistor controlled.T1 temperature sensor and voltage to the base - emitter is compared, through potentiometer P1, with the common point of reference in its D1 and R1.

Transistor remains blocked as long as temperature remains below a certain level, which is set to P1. Base-emitter voltage of transistor will decrease by about 2mV for a temperature increase of about 1 ° C. When the emitter voltage of transistor voltage falls below the cursor P1, the transistor will go into conduction and D2 will light.The values of R1 and R2 are voltage dependence of Ub and relationships can be calculated:
R1 = [(Ub - 0.6) / 5] k, R2 = [(Ub - 1.5) / 15] k

SENSITIVE TOUCH SWITCH BUTTON CIRCUIT USING NE555

This simple Touch Switch Circuit by using a 555 timer IC operated as a MONOSTABLE vibrator. Here the IC is configured as an monostable multivibrator, in this mode the IC activates its output momentarily by producing a logic high in response to a trigger at its input pin#2.
The momentary activation time period of the output depends on the value of C1 and the setting of VR1.
When the touch switch is touched pin#2 is pulled to a lower logic potential which may be less than 1/3 of Vcc. This instantly reverts the output situation from low to high activating the connected relay driver stage.
This in turn switches ON the load attached with the relay contacts but only for the time until C1 gets fully discharged.

BUILDING A LED HALOGEN LAMP FOR MOTORBIKE HEAD-LAMP REPLACEMENT

The post explains a simple 21 watt LED lamp circuit module which can be used as a direct replacement for a standard halogen lamp in motorcycles.


The proposed "halogen" LED lamp replacement module image can be seen below:

Conventional filament type halogen lamp is shown below:

The image at the top shows an example LED lamp replacement for a standard halogen bulb fitting shown below it.

With the easy and extensive availability of LEds, today it's quite possible to make any desired LED lamp module at home for replacing other forms of less efficient lamp options.

So here we'll discuss how to make the proposed halogen LED lamp replacement circuit. Let's learn the procedures:

Referring to the above image, we can see the LEDs are wired over 7 separate PCBs and then wired together to form one single module.

Each board can be seen with 3 LEDs each, constituting a total of 21 LEDs.

3nos LEDs are selected because the supply 12V available from the vehicle allows only 3nos to be connected in series, and series connection facilitates sharing the same current across the three LEDs.

Now since more than 3nos. of LEds cannot be accommodated in series, 7 such strings are connected in parallel with each other for achieving the desired 21 watts.

The above assembly must be done over a well designed heatsink cored glass epoxy PCB.

The entire configuration may be tightly fixed over an thick hexagonal aluminum cylindrical former or base to form the proposed halogen LED module unit. The aluminum will hep to sink the generated heat from the LEDs.

The above unit will strictly require a current controlled driver circuit which can be understood with the following points:

We once again take the help of the versatile LM338 IC for the required current control function.

Referring to the circuit diagram we ca see it in it's simplest current limiting mode. The LEDs consume around 2.5 amps together which is never allowed to exceed by the IC keeping the unit safe from the issue.

Aluminum mount or base design for fixing the LED PCB assembly

Comparison Between Conventional Halogen lamp and LED Halogen lamp Output

Output                              Conventional Incandescent    LED Halogen Lamp

Specs                               Halogen

     

Nominal wattage              55 watts                                       21 watts

Nominal voltage               12V                                               12V

Test voltage                     13.2V                                            13.2V

Color temperature          3200K                                           6000K

Luminous flux                 1500lm                                         2500lm

MUSIC GENERATOR SCHEMATIC CIRCUIT USING UM66

This is a simple project using the IC UM66. UM66 has an inbuilt beat and tone generator. This IC, with its three legs, looks like a transistor. This IC has many versions for playing different songs/beats. This project is suitable for beginners as its circuit is very simple.

 

 The  UM66 series are CMOS IIC’s designed for using in calling bell, phone and toys. It has a built in ROM programs for playing music. The device has very low power consumption. Thanks for the CMOS technology. The melody will be available at pin 3 of UM66 and here it is amplified by using Q1 to drive the speaker. Resistor R1 limits the base current of Q1 within the safe values. Capacitor C1 is meant for noise suppression.

UM66 is a pleasing music generator IC which works on a supply voltage of 3V. the required 3V supply is given through a zener regulator. its out put is taken from the pin no1 and is given to a push pull amplifier to drive the low impedance loud speaker. A class A amplifier before push pull amplifier can be used to decrees the noise and improve out put. UM66 is a 3 pin IC package just looks like a BC 547 transistor.

Music Generator Using UM66 Circuit Diagram

A Continuous Music Generator Circuit Diagram

Parts:

R1 = 4.7K
C1 = 10uF-25v
D1 = 3.3v Zener
Q1 = SK100
Q2 = SL100
IC = UM66
SP = 8 ohm

Pin out of UM66 IC:

1. Output----Melody Output
2. +Vdd-----Positive power supply
3. -Vss------Negative Power supply

Features of UM66T series:

• 62 Note ROM Memory
• Voltage rating: 1.3V to 3.3 V
• Power on reset

24 HOUR TIMER CIRCUIT SCHEMATIC DIAGRAM

Designing long duration timers using conventional RC timing networks are difficult due to the large values needed. For example, a 555 monostable needs a 1M resistor and a 3300uF capacitor just to produce a 1 hour delay, and the accuracy is questionable. Therefore a digital approach has been taken for this design.

Description:

These two circuits are multi-range timers offering periods of up to 24 hours and beyond. Both are essentially the same. The main difference is that when the time runs out, Version 1 energizes the relay and Version 2 de-energizes it. The first uses less power while the timer is running; and the second uses less power after the timer stops. Pick the one that best suits your application.

Notes:
The Cmos 4060 is a 14 bit binary counter with a built in oscillator. The oscillator consists of the two inverters connected to Pins 9, 10 & 11; and its frequency is set by R3, R4 & C3.The green Led flashes while the oscillator is running: and the IC counts the number of oscillations. Although it's a 14 bit counter, not all of the bits are accessible. Those that can be reached are shown on the drawing.
By adjusting the frequency of the oscillator you can set the length of time it takes for any given output to go high. This output then switches the transistor; which in turn operates the relay. At the same time, D1 stops the count by disabling the oscillator. Ideally C3 should be non-polarized; but a regular electrolytic will work, provided it doesn't leak too badly in the reverse direction. Alternatively, you can simulate a non-polarized 10uF capacitor by connecting two 22uF capacitors back to back (as shown).
Using "Trial and Error" to set a long time period would be very tedious. A better solution is to use the Setup tables provided; and calculate the time required for Pin 7 to go high. The Setup tables on both schematics are interchangeable. They're just two different ways of expressing the same equation.
For example, if you want a period of 9 Hours, the Range table shows that you can use the output at Pin 2. You need Pin 2 to go high after 9 x 60 x 60 = 32 400 seconds. The Setup table tells you to divide this by 512; giving about 63 seconds. Adjust R4 so that the Yellow LED lights 63 seconds after power is applied. This will give an output at Pin 2 after about 9 Hours.
The Support Material for the timers includes a detailed circuit description - parts lists - a step-by-step guide to construction - and more. A suitable Veroboard layout for each version is shown below:

 

The timer was designed for a 12-volt supply. However, provided a suitable relay is used, the circuit will work at anything from 5 to 15-volts. Applying power starts the timer. It can be reset at any time by a brief interruption of the power supply. The reset button is optional; but it should NOT be used during setup. The time it takes for the Yellow LED to light MUST be measured from the moment power is applied. Although R1, R2 and the two LEDs help with the setup, they are not necessary to the operation of the timer. If you want to reduce the power consumption, disconnect them once you've completed the setup. If you need a longer period than 24-hours, increase the value of C3.

 

author: Ron J
web site: http://www.zen22142.zen.co.uk

170 WATT AUDIO POWER AMPLIFIER CLASS D SCHEMATIC DIAGRAM

 With ICs LM4651 & LM4652

 
The combination of the LM4651 driver IC and the LM4652 power MOSFET Class D power amplifier IC provides a high efficiency amplifier solution, suitable for self-powered speakers, subwoofers and quality car boosters.
The LM 4651 is a fully integrated conventional pulse width modulator (PWM) driver, containing undervoltage, short circuit, overmodulation, and thermal shutdown protection circuitry. The IC features a standby function which shuts down the pulse width modulation, minimizing supply current. 

The LM 4652 is a fully integrated H-bridge Power Mosfet IC in a TO220 power package. The IC has a built in temperature sensor to alert the LM4651 when the die temperature exceeds the threshold limit.
Used together, the LM4651 and LM4652 form a simple, compact, efficient, high quality power audio amplifier solution complete with protection, normally seen only in Class AB amplifiers. 

 

 

CLICK ON PICTURE TO ENLARGE

 

 The maximum efficiency of this circuit is 85% at 125W with a standby attenuation greater than 100dB. The THD at 10W, 4 ohms, 10 - 500Hz is max. 0.3%. The supply voltage can not exceed ± 22V. 

 

For the best performance a suitable preamplifier is required. With the addition of a preamplifier the gain of the power stage can be greatly reduced to improve performance. The gain should be set to 10 V/V allowing for low gain on the Class D stage with a total system gain high enough to be a complete solution for line level sources. 

 
The input filter used here does not noticeably increase THD performance but will help to maintain a flat frequency response as the Q of the output filter changes with load impedance.
 

 

 Do not attempt to build this amplifier as your first project! Class D high power amplifiers are expensive, difficult to build and a very small error during assembly can lead to total devastation of the power IC or other costly components.

INVERTER / CONVERTER = 12V / ~ 220V

The converter is designed to power various low-power equipment for alternating current 220V from an automotive power source.
The frequency of the alternating current at the output is close to 50 Hz. The output voltage is not stabilized, but it can be controlled with a multimeter and regulated with a variable resistor.
Power of loading no more than 100W.
The diagram is shown in the figure. It is based on the TL594 microcircuit designed for operation in switching power supplies with a push-pull output and pulse-width regulation / voltage stabilization.


The equivalent generation frequency is 50 Hz, it is set by the resistance of the resistor R5, and depends on this resistance and the capacitance of the capacitor C5.
Resistor R4 controls the duty cycle of the output pulses. They can adjust the output voltage.
The outputs of the microcircuit are outputs 9 and 10, antiphase pulses are allocated to them, slightly delayed relative to each other so as not to cause a through current in the output stage circuit at the time of switching. Pulses arrive at the powerful key field-effect transistors VT1 and VT2 . Diodes VD2 and VD3 protect these transistors from negative EMF emissions on the primary winding of a pulse transformer T1.
The T1 transformer is a ready-made low-frequency power transformer with a rated power of 100W, with one primary winding at 220V and a secondary winding at 18V with a tap from the middle. You can try a transformer with a secondary winding of 12V with a tap from the middle or 24V with a tap from the middle. But, in the second case, I'm afraid that the output voltage will be slightly less than 220V.
The transformer is turned on “back to front”, that is, its secondary low-voltage winding now serves as the primary, and the high-voltage primary, as the secondary.
By connecting the load and a multimeter (or another AC voltmeter) with the resistor R4, set the voltage to the load 220V.
Author: V. Teplyakov

 

USB MULTIMETER POWER SUPPLY

Typically, the multimeter is powered by a nine-volt battery type "Krona". It is inexpensive, but it ends abruptly. Moreover, now almost everyone has a device powered by a USB port - laptops, tablets, smartphones, and the corresponding chargers. Here is a description of the voltage converter unit to power the multimeter from any USB port or from a charger with a USB connector. The task of this unit is to increase the voltage 5V, available on the USB-connector, to a voltage of 9V, necessary to power the multimeter.
The figure shows a diagram of a simple unit that allows you to get a stable DC voltage of 9V from the USB port, provided that the load current does not exceed 150 mA. Using such an adapter, it is possible to power not only a multimeter from a USB port, but also other circuits and devices powered by Krona.
The circuit is based on a DC-DC converter on the LM3578AM chip. Since the converter is pulsed, an inductance L1 is installed at the input, which prevents the penetration of pulsed noise into the circuit of the device, the USB port of which serves as a power source. As part of the A1 chips, there is a pulse generator with PWM, and an output key. The key goes to conclusions 6 and 5. Pin 7 is the input of the control protection circuit, which determines the current through the key by the value of the voltage drop across the resistance of the resistors R2-R4. And when it exceeds the permissible value, protection is triggered.

Voltage is pumped at inductance L2. Then, this alternating voltage is rectified by the Schottky diode VD1 and smoothed by capacitors C6 and C7. The output voltage is stabilized by comparing the voltage removed from the R5-R6 divider with the reference voltage generated by the stabilizer, which is part of the microcircuit. The control input is terminal 1. Resistors R5 and R6 form a voltage divider, with which the output voltage is divided so that with the required output voltage of 9V, terminal 1 A1 has a voltage of 1V.
The output voltage is greater, the greater the division ratio of the divider R5-R6. In principle, the maximum output voltage can be made much higher (but not more than 30V). You can increase the output voltage by decreasing the resistance R6 or increasing the resistance R5.
Mounting the converter is most conveniently done on a small printed breadboard.
Chokes L1 and L2 - finished, industrial production.
Conventional resistors have a significant variation in resistance, so if the output voltage is less than 8V or more than 9.5V, you need to choose R5 or R6.

Author: Zhurbin A

USB POWERED LABORATORY POWER SUPPLY

USB is currently a universal computer port to which a wide variety of devices connect. A fairly powerful 5V voltage source is output to USB, so many devices not only exchange data through it, but also are powered by a USB port. These are various scanners, webcams, portable CD or DVD-drives, modems, etc. On the Internet you can find descriptions of very stupid trinkets powered by USB - micro-vacuum cleaners, tea heaters, and even microcoffee makers.
In principle, many other peripheral devices that are not designed for this can be powered from USB, but there are some limitations. In particular, according to the supply voltage, which is only 5V. Despite the fact that peripherals powered by their own network adapters usually require a higher voltage, and even 5V is not always what you need to power many homemade products.

The figure shows a diagram of a simple adapter that allows you to get a stable DC voltage from a USB port adjustable between 1.4 and 35V, provided that the load current does not exceed 350 mA. Using such an adapter, you can power a variety of circuits and devices from a USB port, and even use it as a laboratory source, which is most important when working with a USB laboratory or an affordable set of programs such as those that allow you to turn a PC with a sound card into low-frequency oscilloscope, millivoltmeter, low-frequency generator, frequency meter (such programs are usually available on the Internet for free).

 The circuit is built on IC LT1372, designed to build circuits of DC-DC voltage converters. The built-in generator generates pulses with a frequency of about 500 kHz. The stabilization circuit adjusts the latitude of these pulses and feeds them to the output switch on the output transistor, which is part of the microcircuit. The chip has protection for the output transistor against overcurrent through it. With a current through it of more than 1.3A, protection is triggered. The protection is based on the principle of measuring current by measuring the voltage across the resistance in the emitter circuit of the output transistor. Measuring resistance is part of the chip.
An inductance L1 is connected to the collector of the output transistor, on which the AC voltage is “pumped”. Which is then rectified by the diode VD1 and smoothed by the capacitor C4. The output voltage is stabilized by changing the latitude of the pulses arriving at the base of the output transistor. The sensor for measuring the output voltage is a comparator. Pin 2 should have a voltage of 1.25V, voltage is supplied to this pin from the output of the circuit through a divider on resistors. And the comparator adjusts the pulse width so that it is exactly 1.25V on pin 2. Thus, by adjusting this voltage divider, the output voltage can be adjusted. With the resistance of the resistors R3-R5 indicated in the diagram, the output voltage can be adjusted from 1.4 to 35V.
Since the block was supposed to be universal with the ability to quickly adjust the output voltage, three VD2-VD5 diodes are included in the circuit between pin 2 and the common minus. Their task is to limit the voltage at pin 2 so as not to damage the microcircuit during a sharp rotation of the shaft R4 in the direction of reducing the output voltage.
With an output current of up to 0.35A, a radiator is not required.

 Author: Zhurbin A

SIMPLE LED POWER ADAPTER

No one needs to be convinced about the benefits of using LEDs in lighting. A pre-presented power supply provides the correct diode performance. This system is a surge current stabilizer. The circuit diagram is shown in Fig. 1.

 A constant voltage in the range of 6 ... 17 V can be applied to the stabilizer. The output current is regulated by a PR1 potentiometer.

 In fig. 2 shows the characteristics of the output current as a function of the resistance PR1.


 The change range is from 50 mA to 1.2 A. The MBI1801 chip has built-in thermal protection that protects it from damage. When the temperature reaches 165 ° C, the output is switched off. The device consists of only eight elements and is not difficult to assemble. After assembly, only adjustment of the output current is required. The easiest way to do this is to connect the ammeter in series with the LEDs. Before turning on the power, potentiometer PR1 must be set to maximum resistance. The input supply voltage should be approximately 2 ... 3 V higher than necessary for the diode. Now turn on the power and set the required output current using the PR 1 potentiometer. It may also turn out that with a limit of the output current and voltage of the power source, the MBI1801 chip will need a radiator. It should also be remembered that the minimum supply voltage must be at least 6 V.

SIMPLE POWER SUPPLY MINIATURE SWITCHING VOLTAGE REGULATOR

The stabilizer module is based on the integrated circuit L4960, which contains all the active elements of the pulse converter. Thanks to pulsed operation, the efficiency reaches 70 ... 85%. The output voltage is user-defined. Recommendations: The device is especially recommended for practitioners and designers of electronics to reduce voltage and power supply where high system efficiency is required.





Specifications
 Efficiency: 70 ... 85%,
 input voltage range: 8 ... 50 V DC
 output voltage range: 5 ... 40 V DC
 maximum load current: 2.5 A
 switching frequency: 100 kHz
 thermal fuse tripping temperature : 150ºC

Device description
Good performance was achieved through the use of the L4960 switching regulator. In its composition, this chip contains all the elements important for the correct and reliable operation. These include a soft start system, an output transistor clock generator, a power terminal, thermal protection, and a PWM controller controlled by an error amplifier. Thus, the L4960 does not require the use of too many external components. The parameters of the power supply depend on two components - the inductor L1 and the pulse diode D1.


Components R1, C2 determine the operation of the reference frequency generator. Capacitor C3 together with resistor R2 serve as an error compensation circuit. Capacitor C4 sets the initial speed of the inverter after turning on the power. This capacitor provides a rather slow increase in the pulse duration at the output of the system, which prevents the possibility of transients at the output of the power supply. The task of the diode D1 is to create a path for the reverse current to flow, which is induced by the energy stored in the core of the inductor L1. The lower the resistance, the higher the resulting power supply efficiency. Since the stabilizer operates in a pulsed mode with the order of tens or even hundreds of kHz, the elements of the output filter should have optimal parameters for this frequency range. At the output of the stabilizer, filtering capacitors with a capacity of 150 ... 470 uF can be used. In the presented device, a capacitance of about 200 μF is used, which is divided into two capacitors of 100 μF each (C5 + C6). The use of two capacitors instead of one with a larger capacity is due to very poor capacitor parameters in the higher frequency range, which reduces the quality of filtration and the efficiency of the power source.
Resistors R3 and R4 are a feedback divider that sets the value of the output voltage. This voltage is easiest to adjust by changing the resistance of R3. In the elements of the calculation of the divider, it is necessary to take into account that the internal reference voltage is 5.1V. Table 1 shows the values of R3 for the most typical output voltages, LED D2 indicates a stabilizer, and resistor R5 limits the current flowing through it.



The resistance value R5 shown in the diagram allows the diode to operate in the range of the output voltage 5 ... 15V. If the output voltage increases above 15 V, it is worth increasing the value of the resistance R5, which will prevent damage to the diode D2.
The circuit board and the arrangement of the elements are shown in Figure 2.


The correct assembly procedure when applying generally accepted principles will ensure immediate and trouble-free activation of the power source. The US1 chip together with the D1 diode must be screwed to the radiator, while it is necessary to isolate the radiator from the diode radiator. To fasten the screws, use mica insulators and plastic bushings.

9V SIMPLE POWER SUPPLY

Nowadays, different battery powered devices typically use 3 V two-cell batteries. In old times, there was a “battery” of 9 V everywhere, both in the remote controls and in the desktop electronic clock with an LCD. By the way, as for the electronic clock, the author has exactly the same ones on the LCD and powered by battery, with Soviet melodies in the alarm clock. But, unfortunately, they consume significant current, and they do not have enough modern “battery” (6F22 battery) for more than a month. Therefore, it was decided to look for an alternative power source for them - a network one.

First, an unsuccessful attempt was made to supply a voltage of 5.4 V from “charging” for a cell phone. The clock seemed to work, but it began to malfunction, for example, when switching from “23-59” to “00-00” the number “08-00” appeared immediately after which the clock went two minutes later, that is, every minute the reading increased by two minutes.
Then it was decided to make a compact voltage source of 9 V and mount it in a volumetric way in the battery compartment of the watch. The power supply is assembled according to the rectifier circuit with a step-down voltage stabilizer on the Zener diode VD5 and capacitor C1, the reactance of which takes on excess voltage (Fig. 1).
 The output current of the power supply is not more than 20 mA, but this is more than enough to power the clock with the LCD. Capacitor C2 was taken with a relatively large capacity for good reason - it supports the watch’s power for several minutes, and therefore short-term disconnections from the mains do not disrupt the watch.
In the circuit, the Zener diode D814V can be replaced by any zener diode with a voltage of 8-10 V. Diodes 1N4007 - any rectifier low-power, Capacitor C2 - the larger the capacity, the better. But it is possible and only 10-100 uF, - the circuit will work, but will not hold voltage when turned off from the network.
Based on the same circuit, a universal power supply was also made, from which various voltages can be obtained to power a variety of low-power equipment. The diagram of this power supply is shown in Figure 2. From this power source, voltages of 3 V, 6 V, 9 V and 12 V can be obtained. Moreover, even simultaneously.

 The bottom line is that the zener diode in this circuit is replaced by a chain of four zener diodes in series of 3 V each. In total, they give 12 V, so if you remove the voltage from everyone, it will be exactly 12 V. But, if you take the voltage from only one zener diode, VD8, this voltage will be 3 V. With two zener diodes (VD8, VD7), voltage 6 In, with three zener diodes (VD8, VD7, VD6) there will be 9 V, on a with all four, as already mentioned, 12 V.
Naturally, the capacitor C2 should now be at a voltage of at least 12 V (in this case, 16 V).
As the Zener diodes VD5-VD8, you can use any zener diodes for a stabilization voltage of 3 V. For example, 1N59876, 1N4683, BZX84C3V0LT1 and others. You can use zener diodes for other voltages, for example, if you take zener diodes not for 3 V, but for 3.3 V, the output voltages will be 3.3 V, 6.6 V, 9.9 V and 13.2 V, respectively. Zener diodes can also have different stabilization voltages, and their it does not have to be exactly four. Accordingly, there will be different output voltages and a different number of outputs. In any case, the capacitor C2 should be at a voltage not lower than the largest of all output.
Author: Maykov S.

 Additional warnings for mains-powered appliances/devices................
 Considering the hazards that may occur during system installation and use,
maximum safety is only ensured if the product is installed in strict observance
of current legislation, standards and regulations.Ensure that all material to be used is in perfect condition and suitable for its
intended use.Before accessing internal terminals of the product, all power circuits must be
disconnected..........

RGB LED STRIP CONTROL UNIT

Nowadays, lighting with LED strips is very popular. The use of RGB LED strips is especially interesting, because it allows you to get the most diverse color of lighting.
This device is designed to control an RGB LED strip or three LED blocks with common anodes. The device provides 13 modes of operation of the LED strip:

 Off state.
 All LEDs are on.
 The red LEDs are on.
 The green LEDs are on.
 The blue LEDs are on.
 Red and green are included.
 Red and blue are included.
 Green and blue are included.
 Smooth color switching.
 Switching colors.
 Ripple red.
 Ripple green.
 Throbbing blue.
The choice of mode is carried out with a single button. After turning on the power or pressing it, a sequential enumeration of the modes begins. To stop at the desired mode, you must press the button continuously during its playback. After that, the selected mode will work.
The circuit is based on the low-cost microcontroller PIC12F629. To smoothly change the brightness of the LEDs, the pulse width modulation method is used. This microcontroller does not have a PWM block, so PWM is implemented in software here.
Fig. 1
This microcontroller has a small amount of memory, so I had to save it. As a result, it was decided to abandon the manual adjustment of the brightness of the glow, and use a low-frequency PWM with a frequency of 400 Hz.
After power-up, the microcontroller initializes its internal registers and peripheral devices and loads the last operating mode. Pins 5, 6, and 7 send signals to field effect transistors Q1, Q2, and Q3, which control the colors of the LED strip.
A 12-volt power supply is usually used to power an LED strip. Therefore, to provide power to the microcontroller, a 5 D voltage regulator is installed in the circuit on the A1 chip.
Installation is made on a small printed circuit board with one-sided arrangement of printed tracks.
Fig. 2
Transistors IRLU024N can be replaced with some analogs, for example, such - STD12NF06L, STD20NF06L, 2SK2229, 2SK2782, 2SK2926.
Button S1 - round miniature with leads for wires. On the board for its installation, the holes are made oval (two holes are nearby and dig out material between them).

Firmware

Author: Gorchuk N.V.

HOME WATER IRRIGATION SYSTEM FOR FLOWER POTS FOR 24HR / 7

A 24/7 Home Water Irrigation System for Flower Pots

A home water irrigation system that will supply enough water for the plants to keep them healthy and happy round the clock.    This system needs no water timers.   

How?

To use wicking action to supply water to the plants.  With this system ,  one can easily check if  there is enough water delivered to the pots and plants. 

What is Wicking Action?

It is an absorption  of liquid through capillary action by a material such as candle wick, paper or fabric cloth or strip.  In this irrigation system,  fabric strips are used instead of wicks as they are economical and easy to use;  furthermore,  one could control the rate of water flow easily 

What’s needed? 

1.  A length of 13 mm PVC to deliver water to the flower pots or plant	Click to enlarge picture if necessary
2.  A plastic water cup with lid for each plant.
3.  4 mm  silicone tube often used in aquarium,  preferably black in color to avoid algae growth.
4. Dremel drill or similar with abrasive grinding Stone of 3.5 mm tip
5.  A few sheets of woven type fabric filter cloth
6   Few glue sticks
7.  Mini float valve so that 4 mm or larger silicon tube could supply water through the float valve.
8  Plastic storage box about 150 x 150 x 120 mm

Step by Step

1.  Making plastic box stand
a)  Cut a strip of PVC measuring about 15 x 100 mm to make 2 stands for the cups as shown
b)  Heat the larger end of the PVC strip with a lighter and make it flat to form a  base to fix onto the bottom of the plastic cup using hot glue stick.
c)  Once the stand is ready,  drill 2 holes,  one on the top and the other at near bottom of the cup.  Making sure the near bottom hole is about 3.5 mm for the 4 mm silicon tube to be inserted tightly with no water leak. Make a horizontal cut at the top hole using a scissor. d)  Cut a long fabric strip of  about 5 mm width with one of its ends "threaded" through  the cup, making sure the strip will pass through the horizontal cut at the top hole as shown e)  Extend the 5 mm fabric strip if necessary so that the strip can be wrapped round the PVC stand.  A wedge made at the end of stand can be used to terminate the fabric strip. f)  With the cup cover fix,  the cup is ready to be used
2.  Constructing the Water tank
a)  At  about 100 mm from the bottom,  drill  a  hole of size to fit the mini float;
b)   At the opposite bottom end,  drill another hole of size to fit a PVC socket or otherwise to fix a 6 mm flexible PVC hose.   The hose will allow tank to be moved to adjust water level..    Alternatively in areas where water cannot be  piped through, one can use invested mineral water bottles as shown in the second picture.
3.  Constructing Water Distribution pipe
a)  For each cup,  make a 3.5 mm hole on top of the distribution pipe for the 4 mm silicon tube to be inserted.   There should not be any water leakage if the tube in inserted  properly;  if necessary,  apply UHU Glue to seal the leak. b)  Connect the other end of the silicon tube to the plastic water cup as shown.
4.  Installation
a)  Tank Installation Select a suitable place so that the water distribution pipe will be 15-20 mm below the surface of the earth in the pot.  If the pot is too large and too high,  drill appropriate holes in the pot for the tube and make sure the earth level of the pot is not higher than 20 mm from the distribution pipe. If necessary,  use bubble leveler to ensure that the distribution pipe is truly horizontal.  This will ensure water will find its level to supply water to the cups.  Thereafter,  fix the pipe in position by using pegs or pipe hangers. b)  Flower pot placement Adjust the height of the pot using padding so that all the surfaces of the earth in the pots are at about the same level;  if necessary, construct small stools for the smaller flower pots.
5.  Testing and commissioning
a)  Adjust the water dripping  rate to about 2 drops of water per 5 minutes or about 30-50 mils per day.  This dripping rate can checked by hanging the cup's stand to the pipe as shown using rubber bands b)  The dripping rate can be adjusted  by:  1.  Increasing the depth of the water level in the cup; 2.  Trimming the width of the fibre strip to reduce the water wicking action
6.  Water Filtration System
Water filters will be needed to get rid of algae which will easily clog up the small pipes or tubes.  One should place water filtering media in the following places: a)  in the water tank b)  along and in-line with the water distribution pipe as shown
7.  Maintenance No system can work properly without  maintenance.   Once a while,  one should do the following; a)  Monitor the water level in the cup,  making sure that water level is about the same; b)  Place paper testing strip  under each flower pot to test the wicking action.  Paper should not be  too wet or too dry.  One can also try to use finger to test the wetness of the soil. c)  Clean up the filters and clear the clog in the silicon tube as and when necessary.  Bicycle pump is a good tool to apply pressure to clear any water clog. If one found no water in the cup,   one can do the following: a)   Fill the water tank as high as possible to force water to flow into the cup; b)  Pump water into the cup by massaging or pressing the silicon tube repeatedly.

Note :   The system will work best in low water pressure as silicon tube are not for high pressure application.   High level water cistern should be used as water source instead of the high pressure water mains.