The post explains a simple yet very useful 0 to 50V dual power supply circuit which also includes a wide range current control feature right from 0 to 10 amps. The idea was requested by Mr. Tamam.

Technical Specifications

It was my long term dream to build a 2 channel power supply for personal use, I have seen a lot of circuits, but those does not fit my criteria.
However, please take a look at the following requirements and let me know if its possible or not, if possible I will be the happiest person in the world.

1. Output voltage range: -50V to 0V to +50V ( must be adjustable by individual channel )

2. Output Current range: 0A to 10A  ( must be adjustable by individual channel )

3. Output would be Duel channel, means total 6 outputs,

Channel 1 (Positive, GND, Negative)     Channel 2 (Positive, GND, Negative)

4. Power Supply Unit should contains 2 Voltmeters and 2 Ammeters (Analogue) for 2 individual channel.

5. Power Supply Unit must have short circuit protection and cooling fan featured and extreme heat protection.

6. I don't want to use any PIC or AVR, so please avoid those.

Money is not a matter here, I will spend continuously until above requirement meets.
Even If I need any custom transformer I will order and make it from our local area.
I have seen many ready made power supply in market but I want to make it by own hand. You just show me the way... please bro, I will be pleased to you for lifetime.

Thank you very much !!

Best Regards,


 Circuit Diagram




The Design

The basic design of the proposed 0 to 50V variable dual power supply circuit with 0 to 10 amp variable current facility is shown in the above figure.

The entire design is transistor (BJT) based and is virtually indestructible. Moreover it's equipped with an over load and over current protection features.

The two section included in the design are exactly similar with  their configurations, the only difference being the use of PNP devices in the lower configuration while NPN in the upper configuration.

The upper NPN design is configured to produce a variable response right from 0.6V to 50V positive while the lower PNP section becomes responsible of producing an oppositely identical response from -0.6V to -50V output.

The Transformer Specs

The maximum limit could be suitably changed simply by changing the voltage rating of the transformer. However for higher voltages you may have to appropriately upgrade the BJT voltage ratings accordingly.

In both the designs, P2 executes the function of varying the voltage levels as desired by the user, while P1 functions as the current regulator and is used for adjusting or setting the output anywhere from 0 to 10 amp current. Here too the maximum rating depends on the selection of the transformer amp rating and may be changed as per individual preferences.

T1s in the both the sections become the fundamental part or the heart of the entire voltage control functioning in the circuit, which becomes possible due to the popular common collector configuration of the devices.

The other two active BJTs only help to implement the same just by controlling the base power of the T1s thus making it possible to adjust the thresholds to any desired user defined voltage and current levels, as per the ratings of the transformer or the input supply.

Parts list

R1 = 1K, 5 watt wire wound

R2 = 120 Ohms,

R3 = 330 Ohms,

R4 = to be calculated using Ohms law, R = 0.6/Maximum Current Limit, Wattage = 0.6 x Maximum Current Limit

R5 = 1K5,

R6 = 5K6,

R7 = 56 Ohms,

R8 = 2K2,

P1,P2 = 2k5 presets

T1 = 2N6284 + 2N2222(NPN), 2N6286 + 2N2907(PNP)

T2, T3 = BC547B (NPN) BC557B (PNP),D1, D2, D3, D4 = 6A4,

D5 = 1N4007,C1, C2 = 10000uF/100V,

Tr1 = 0 – 40 Volts, 10 Amp

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