Introduction:
A voltage follower also called voltage buffer or unity gain amplifier is an operational amplifier in which the voltage at the output is equal to the voltage at the input which means the input and output voltages are the same. It has a voltage gain of one (unity) which means it does not amplify the incoming signal at the output. The voltage follower has a high input impedance which makes it suitable for the circuits where input and output isolation is needed, while a low output impedance which makes it suitable for a voltage divider circuit.
The circuit explained below consists of a few simple components in which the main component is an amplifier IC LM741. The main function of the IC is to boost up the AC and DC signal and for performing mathematical operations.
Hardware Components
The following components are required to make Voltage Follower Circuit
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1. | Operational Amplifier IC | LM741 | 1 |
| 2. | Variable Resistor | 10KΩ | 1 |
| 3. | Variable Resistor | 1KΩ | 1 |
| 4. | Battery | 9V | 1 |
| 5. | I/P Signal source (Function Generator) | – | 1 |
LM741 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of LM741
Voltage Follower Circuit
Construction & Working:
The circuit is easy to build with minimum hardware. It uses an IC LM741, a variable resistor of 10K, a general-purpose 1K ohm resistor, a battery, and an input signal source.
The input is applied to the non-inverting terminal of the IC, while the inverting terminal is coupled with the output for the negative voltage feedback. The variable resistor is used for varying the input voltage between 0-9V DC since the circuit has a voltage gain of unity, therefore,
Gain = output voltage/input voltage
Since gain/Av = 1, therefore
1 = Vo/Vin and, Vo = Vin
We can calculate the voltage, current, and resistance using Ohm’s law:
Current = Voltage/ Resistance
OP-AMP Pin Details:
It can be operated using a dual power supply or a battery and the maximum supply voltage can be 22V. It can be applicable for op-amps, comparators, multivibrators, filters, etc.
The pin configuration of the IC is given below:
Applications:
Voltage follower can be used in the following applications:
- It can be used to build active filter circuits.
- It can be used as buffers in logic gates.
- It is used in bridge circuits by transducers.
- Furthermore, it can also be used in sample and hold circuits.
Advantages:
There are numerous advantages of voltage followers. Some are listed as follows:
- It has a voltage gain of unity (one).
- It does not use any current from the input.
- It gives power and a current gain.
- Furthermore, it does not change the amplitude of the input signal.
- Likewise, it avoids loading effects.
