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Multi voltage power supply circuit using IC-78xx series

We like a multi voltage power supply circuit. It has 2 dual output,5V and 12V. There is positive, negative and ground. All has 1A max current.

  • The 12V are +12V,-12V, Ground
  • the 5V are +5V, -5V, Ground

It is proper common analog and digital circuits.

Sometimes, we use only 5V or 12V does not enough.  We need to have many voltage terminals. The equipment it easy to buy and affordable.

Multi voltage power supply circuit using IC-78xx series

How this circuit work
First of all, the transformer-T1  reduces  AC voltage from 220V or 170V (US)  down to about 15 volts.  Next, the AC goes to D1 through D4, full wave bridge rectifier, act as a rectifier AC to DC.

Then there are capacitors -C1, C2, C5 and C6 to smooth the Pulsed DC into a certain DC voltage, unregulated.

It flows through to the pin 1 (Vin) of IC1 and IC2, DC voltage regulator. Which IC1 (LM7812) will keeps fixed output voltage to reduce of + 12 volt. And also IC2 (LM7912) is negative fixed voltage regulator to -12 volts through the pin 3 (Vout) of IC1 and IC2.


And there are more capacitors C3, C4, C7, and C8. To filtered to low ripple voltage. This part we have the output voltage regulator at +12 volts and -12 volts.

When T2 reduce the AC voltage from 220 volts down to 9 volts. And D5 through D8 diode is bridge rectifier to change the AC to DC Cpulsed DC).

After that, these capacitors C9, C10, C13, and C14 will smoothes (filter) from the pulsed DC to a steady DC voltage.

Then the current flow through to the pin1 (Vin) of the IC3, and IC4. By IC3 (IC-7805) is a positive voltage regulator IC, 5V fixed output.

And IC4 (7905) is negative voltage regulator IC,-5 volts fixed output at pin3. And then flows to more smoothing with C11, C12, C15, and C16. Which the output voltage of +5 volts and -5 volts are suitable for a most digital circuit that uses 1A max.

Also Multi voltage power supply circuit

Convert two-level DC voltage 5V, 12V They use a base of LM7805-IC, For digital and analog that use current lower than 1 amps.

This Post Has One Comment

  1. I Want To Make This Project “Multi voltage power supply circuit using IC-78xx series”
    Please Help With The Procedure Soon And Downloadable WriteUp Material

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