Introduction
Almost all electronic devices need a power supply to operate. A device that provides electric current to the load is called a power supply. It converts the electric current into the right current, voltage, and frequency to power up the load. A dual power supply is a type of power supply that provides a negative and a positive voltage to the load. It is a regular DC power supply. The circuit containing tubes or transistors needs a dual DC power source.
The 12V and 5V dual power supply is a simple circuit that provides 12V and 5V DC voltage at the output after processing through a few steps. The circuit uses voltage regulator IC 7812 and 7805 which belongs to the 78XX series, as its main components, and a few other components which regulate the voltages to 12V and 5V respectively.
Hardware Components
The following components are required to make 12V & 5V Dual Power Supply Circuit
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1. | Step down transformer | – | 1 |
| 2. | Diode | 1N4007 | 1 |
| 3. | Regulator IC | L7812, L7805 | 1 |
| 4. | Capacitor | 1000µF, 100µF & 0.1µF | 1 |
| 5. | Resistor | 2KΩ & 1KΩ | 1 |
| 6. | LED | 5mm | 1 |
7805 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of 7805
7812 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet 7812
12V & 5V Dual Power Supply Circuit
The 12V and 5V dual power supply circuit diagram is given below:
Working Explanation
The circuit provides regulated DC output after processing the input signal in a few steps.
Transformer: The transformer is a basic part of a power supply circuit. It steps down the input signal of 110, 230V AC to 15V AC signal. A device that works on the principle of electromagnetic induction is called a transformer. It transfers electrical energy from one circuit to another. It generally increases or decreases the AC voltage.
Rectifier: The rectifier circuit mainly consists of diodes, it converts the bidirectional AC signal into a unidirectional DC signal by eliminating one side of the AC signal and allowing only unidirectional current to pass through.
Filter: The DC signal after rectification consists of AC ripples and voltage fluctuations is fed into capacitor C1 which removes most of the AC ripples from the signal.
IC 7812: The filtered signal is fed into voltage regulation IC which receives the unregulated DC voltage at its input and provides regulated 12V DC at its output.
In the end, the capacitor C2 is used to filter out the high-frequency ripples remaining in the output signal to provide a ripple-free 12V DC output.
IC 7805: Further the 12V DC signal is again filtered and fed into the IC 7805 which takes in the input signal and provides regulated 5V DC at its output and the signal is again filtered to remove the high-frequency ripples by using capacitor C4.
LED1 and LED2 indicate the presence of 12V DC voltage and 5V DC voltage at the output respectively.
Applications:
- The dual power supply is used to power up the op-amp since OP-AMPS needs to swing bipolar output voltages.
- Dual power supplies can be used in power banks, cell phone charging circuits or battery-less power circuits, etc.
- The dual power supply is also used in generators.
- Hence, there are a number of applications that take advantage of 5V and 12V dual power supplies.
