Introduction:
A regulated power supply is an essential part of many electronic devices and circuits. These power supplies have semiconductor material employed in them that has a fixed current and voltage rate. The IC 7805 belongs to the 78XX series of linear voltage regulators which produces an output of regulated 5V since most of the TTL ICs work on 5V logic, and therefore we need a consistent 5V power supply. The IC 7805 hence is useful for this purpose.
The 7805 IC is a three-terminal voltage regulator which has a fixed output of 5V and is applicable in a wide variety of applications. The major characteristics of the IC are as follows:
- It provides the current up to 1.5A with the heat sink.
- It operates with a current of 5mA.
- It works with only a few components.
- Furthermore, it has a thermal shut down and internal current limiting features.
Hardware Components
The following components are required to make a 7805 Voltage Regulator IC Circuit
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1. | Step-down transformer | 0-9V AC / 1 amps | 1 |
| 2. | Diodes | 1N4007 | 4 |
| 3. | Regulator IC | 7805 | 1 |
| 4. | Capacitor | 47μF, 10μF, 0.1μF | 1 |
LM7805 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of LM7805
LM7805 Voltage Regulator Circuit
Working Explanation
The mains AC supply is converted into unregulated DC supply and then at the output of the circuit, regulated 5V DC supply is achieved. The circuit works in a few steps which are as follows:
Transformer: A device that transfers the signal from one circuit to one or more circuits either by increasing (step-up) or decreasing (step down) as required using a principle of electromagnetic induction. Here the transformer steps down the 230V mains source to 9V AC.
Rectifier: Rectifier circuit operates using diodes that convert the AC signal into a DC signal by conducting a pair of diodes for each half cycle.
Filter: The capacitor is responsible for smoothening the DC signal.
IC 7805: The output from the capacitor acts as an input for an IC which converts the unregulated DC signal into the regulated 5V DC signal which is received at the output.
Applications & Uses:
The IC 7805 is used in various circuits, the key applications are:
- Variable DC voltage regulator
- Dual regulated voltage supply
- Phone charger circuit
- Power supply for UPS
- Current regulator
- Portable CD player
- Inductance meter and many others.
Hence, the 7805 voltage regulator IC has applications in many circuits.
