This 12V dual power supply circuit is like having two separate batteries in one.
It provides two 12V outputs, one positive and one negative with a shared ground.
This is particularly useful for electronics projects like audio amplifiers where you need both positive and negative voltage to make the sound work properly.
It is like having all the power you need in a neat little package.
Circuit Working:
Parts List:
| Category | Component | Quantity | Notes |
|---|---|---|---|
| Capacitors | Ceramic 0.1µF | 2 | |
| Electrolytic 1000µF 25V | 2 | ||
| Semiconductors | IC 7812 | 1 | |
| IC 7912 | 1 | ||
| Bridge Rectifier diodes 1N5402 | 4 | ||
| Transformer 14-0-14V/1Amp | 1 |
Here is a standard symmetric power supply using positive and negative voltage regulator ICs.
It provides +12V and -12V DC with a common ground, suitable for powering amplifier circuits requiring well regulated symmetrical power.
The supply can deliver 1 ampere of current.
To achieve this, a 14-0-14V 1 ampere step down transformer is used to reduce 230V AC to 14V DC, which is then rectified by a standard full wave bridge rectifier composed of diodes 1N5402 D1 through D4.
Capacitors C1 and C2 are employed to smooth out any ripples in the low voltage AC.
Two regulator ICs are utilized to generate the +12V and -12V DC outputs.
IC1 is a 7812 positive regulator providing a regulated +12V output, while IC2 is a 7912 negative regulator.
Note that the pin configurations for IC2 are slightly different from those of the 7812.
Refer to the schematic for the symmetric power supply for the correct connections.
The regulated outputs from the regulator ICs are accessible from pin 3 which can be connected to power the circuit.
Capacitors C3 and C4 act as noise filters to ensure a clean DC output.
Formula:
Finding the Filter Capacitor Value in a 12V Dual Power Supply Scheme.
The filter capacitor value is computed using the following formula:
C = I / (2 * f * Vpp)
where:
- C is the capacitance in farads
- I is the load current in amperes
- f is the input frequency in hertz
- Vpp is the desired peak to peak ripple voltage in volts
Note:
Use a bigger value for the capacitor than what was estimated for better filtering.
You may want extra filtering stages or voltage regulators if you require very low ripple voltage.
You may compute and choose the right filter capacitor for your 12V dual power supply circuit by using these procedures and taking the extra considerations into account.
How to Build:
To build a Simple12 Volt Dual Power Supply Circuit follow the below mentioned steps.
- Gather the components mentioned in diagram.
- 14-0-14V, 1 ampere step down transformer
- Full wave bridge rectifier four diodes 1N5402
- Two voltage regulator ICs: 7812 positive and 7912 negative
- Capacitors: C1, C2, C3 and C4 refer to the schematic for values
- Other necessary components like wires, soldering iron PCB, etc.
Assemble the Circuit:
- Connect the 230V AC input to the primary side of the transformer.
- Connect the secondary side of the transformer to the input of the full wave bridge rectifier.
- Connect the output of the rectifier to capacitors C1 and C2 observe polarity.
- Connect the output of the capacitors to the input pins of the regulator ICs.
- Connect the output pins 3 of the regulator ICs to capacitors C3 and C4 observe polarity.
Check Connections:
- Double check all connections against the schematic to ensure they are correct.
- Make sure all components are properly connected and soldered.
Test the Circuit:
- Use a multimeter to check the output voltages at the regulator ICs output pins.
- Verify that the +12V and -12V outputs are present and stable.
Adjustments:
- If necessary, adjust the circuit or component values to achieve the desired output voltages.
Enclose the Circuit:
- Once the circuit is working correctly enclose it in a suitable housing to protect it from external elements.
Final Testing:
- Perform a final test to ensure that the power supply is functioning correctly and providing the required voltages and currents.
Use with Caution:
- When using the power supply, exercise caution especially with high voltages, to prevent accidents or damage to the circuit.
Note:
- Please note that working with electrical circuits involves risks.
- If you are not familiar with electronics or unsure about any step seek assistance from someone with experience or consult a professional.
Conclusion:
A 12V dual power supply circuit provides two separate 12V DC outputs, one positive and one negative, along with a common ground.
It is commonly used in electronic projects requiring a symmetrical power supply such as in audio amplifiers.