NI-AMP
Non-inverting amplifier circuit
Uses an amplifier feedback arrangement to amplify a signal without the intended polarity inversion.
Schematic
Symbols · BUF
Op-amp voltage follower
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.
- 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.
Read the source: University tutorials: amplifier configurations and signal processing · ADA4522-1 — operational amplification
Schematic · BUF
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.
A distinction that matters
A non-inverting amplifier has a resistor divider in the feedback path and gain greater than one.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
University tutorials: amplifier configurations and signal processing
Public tutorial material on op-amp configurations including the follower.
ADA4522-1 — operational amplification
Manufacturer operational amplifier documentation.
About this graphic
This illustration was authored independently by Elora Grid to explain the concept. It is not reproduced from a customer drawing, an official standard graphic or a manufacturer CAD file. Its correspondence to an exact IEC or IEEE symbol identifier has not been certified.
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