The 7805 is a three-terminal voltage regulator that has become ubiquitous in electronic circuits. It is a linear regulator that provides a fixed 5 volts output from a higher input voltage. A wiring diagram is a visual representation of the connections and interconnections between electronic components. This article will provide a detailed guide on the wiring diagram of the 7805 voltage regulator.
Components Needed to Wire 7805
Before we dive into the wiring diagram, we will list the necessary components needed to wire the 7805 voltage regulator. They are;
| Component Name | Component Purpose |
|---|---|
| 7805 voltage regulator | To provide a fixed 5 volts output from a higher input voltage |
| Input DC power supply | To supply the input voltage to the 7805 regulator |
| Output capacitors | To suppress transients and output voltage fluctuations |
| Filter capacitors | To remove ripples and power supply noise |
7805 Voltage Regulator Pinout
The 7805 voltage regulator has three pins; the input, output, and ground. The input pin is where the higher input voltage is provided, the output pin is where the fixed 5 volts output is obtained, and the ground pin is where the ground of the circuit is connected. Below is a summary of the pinout configuration of the 7805 voltage regulator;
| Pin Number | Pin Name | Pin Purpose |
|---|---|---|
| 1 | Input | Where the higher input voltage is provided |
| 2 | Ground | Where the ground of the circuit is connected |
| 3 | Output | Where the fixed 5 volts output is obtained |
Wiring Diagram of 7805 Voltage Regulator
The wiring diagram of a 7805 voltage regulator is simple and straightforward. It involves connecting the input and output capacitors and the input and output power supply to the three pins of the 7805 regulator. Below is the wiring diagram of the 7805 voltage regulator;
Connection of Input Capacitor
The input capacitor is connected between the input pin and the ground pin of the 7805 voltage regulator. Its purpose is to suppress transients and voltage spikes that may occur in the input voltage supply. A value of between 0.1uf to 10uf ceramic capacitor is suitable for this function. The positive pin of the capacitor is connected to the input pin of the regulator, while the negative pin is connected to the ground pin of the regulator.
Connection of Output Capacitor
The output capacitor is connected between the output pin and the ground pin of the 7805 voltage regulator. Its purpose is to suppress output voltage fluctuations that may result from changes in the load current. A value of between 1uf to 100uf electrolytic capacitor is suitable for this function. The positive pin of the capacitor is connected to the output pin of the regulator, while the negative pin is connected to the ground pin of the regulator.
Connection of Input Power Supply
The input power supply is connected between the input pin and the ground pin of the 7805 voltage regulator. Its purpose is to provide the higher input voltage that will be regulated down to a fixed 5 volts output. The positive pin of the power supply is connected to the input pin of the regulator, while the negative pin is connected to the ground pin of the regulator.
Connection of Output Power Supply
The output power supply is connected between the output pin and the ground pin of the 7805 voltage regulator. Its purpose is to distribute the fixed 5 volts output to the rest of the circuit. The positive pin of the power supply is connected to the output pin of the regulator, while the negative pin is connected to the ground pin of the regulator.
FAQs
1. What is the voltage rating of the input power supply for the 7805 regulator?
The voltage rating of the input power supply for the 7805 regulator should be higher than the required 5 volts output by at least 2 volts. For example, if a 5 volts output is desired, the input voltage supply should be between 7 volts to 35 volts.
2. Can the input and output capacitors be omitted in the 7805 voltage regulator circuit?
No, the input and output capacitors cannot be omitted in the 7805 voltage regulator circuit. The input capacitor is necessary to suppress transients and voltage spikes that may occur in the input voltage supply, while the output capacitor is necessary to suppress output voltage fluctuations that may result from changes in the load current.
3. What is the maximum current that the 7805 voltage regulator can supply?
The maximum current that the 7805 voltage regulator can supply varies with the input voltage and environmental conditions such as temperature. Generally, the maximum current that the 7805 regulator can supply is about 1A.
4. Can the 7805 regulator be used to step up voltage?
No, the 7805 regulator cannot be used to step up voltage. It is a linear regulator that provides a fixed 5 volts output from a higher input voltage.
5. What is the efficiency of the 7805 voltage regulator?
The efficiency of the 7805 voltage regulator is not very high. It is a linear regulator that dissipates excess power as heat. The efficiency is given by the ratio of the output power to the input power, and it is typically less than 50%.
In conclusion, the wiring diagram of a 7805 voltage regulator is simple and straightforward. The components needed include the 7805 voltage regulator, input and output capacitors, and input and output power supplies. The wiring involves the connection of the input and output capacitors and input and output power supplies to the three pins of the 7805 regulator. The input capacitor is connected between the input pin and the ground pin of the regulator, while the output capacitor is connected between the output pin and the ground pin of the regulator. The input power supply is connected between the input pin and the ground pin of the regulator, while the output power supply is connected between the output pin and the ground pin of the regulator.
