# Op-amp voltage follower

Canonical URL: https://eloragrid.ai/symbols/op-amp-voltage-follower
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: BUF
Drawing use: Schematic
Reference families: Manufacturer

Op-amp with its output tied directly to the inverting input, giving unity gain and a low-impedance output.

## In plain English

### What does Op-amp voltage follower mean?

A voltage follower connects the op-amp output straight back to the inverting input and applies the signal to the non-inverting input. The output equals the input, but it is driven from a low impedance, so a high-impedance source can drive a load without being disturbed.

### A simple example

Followers appear as buffers after voltage dividers, references, sensors and sample-and-hold capacitors, and before ADC inputs. On schematics they are easy to recognise by the direct feedback wire with no resistor.

### What the drawings help you do

The circuit does not guarantee stability with heavy capacitive loads, and not every op-amp is unity-gain stable. Check the part selection and any isolating resistor at the output.

### This particular reference

Op-amp with its output tied directly to the inverting input, giving unity gain and a low-impedance output. A non-inverting amplifier has a resistor divider in the feedback path and gain greater than one.

### Terms

- Normally open / normally closed: The contact state in the normal condition defined for the drawing.
- Terminal: An identified point where a conductor connects.
- Signal: Electrical information passed between devices, rather than necessarily the main power supply.

Concept diagram: Identify the device and form → Read the connections and state → Check the equipment reference
A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.

- [University tutorials: amplifier configurations and signal processing](https://wiki.analog.com/university/courses/tutorials/index)
- [ADA4522-1 — operational amplification](https://www.analog.com/en/products/ada4522-1.html)


## What it represents

A voltage follower connects the op-amp output straight back to the inverting input and applies the signal to the non-inverting input. The output equals the input, but it is driven from a low impedance, so a high-impedance source can drive a load without being disturbed.
Followers appear as buffers after voltage dividers, references, sensors and sample-and-hold capacitors, and before ADC inputs. On schematics they are easy to recognise by the direct feedback wire with no resistor.
The circuit does not guarantee stability with heavy capacitive loads, and not every op-amp is unity-gain stable. Check the part selection and any isolating resistor at the output.

## How to read it

- A direct wire from output to minus input with no resistor indicates a follower.
- Check unity-gain stability for the selected part.

## Information to show or reference

- Show the direct feedback connection.
- Note any output isolation resistor for capacitive loads.
- Confirm the selected op-amp is unity-gain stable.

## Important distinction

A non-inverting amplifier has a resistor divider in the feedback path and gain greater than one.

## Facts

- Gain: Unity
- Purpose: Impedance buffering
- Artwork scope: Original educational illustration; consult the applicable standard and the selected device documentation for the exact graphic

## Public references

- [University tutorials: amplifier configurations and signal processing](https://wiki.analog.com/university/courses/tutorials/index) — Analog Devices. Public tutorial material on op-amp configurations including the follower.
- [ADA4522-1 — operational amplification](https://www.analog.com/en/products/ada4522-1.html) — Analog Devices. Manufacturer operational amplifier documentation.

## Graphic scope

Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.