Non-Inverting Gain and Followers

Voltage Follower Copies Input

direct feedback makes gain one

A voltage follower uses direct feedback to make the output copy the input while buffering the next load. The 5 V copy is exact for an ideal op-amp with enough headroom; real followers have input offset, finite output current, slew rate, bandwidth, rail swing limits, noise, and measured error.

A voltage follower is the non-inverting feedback contract with direct output feedback. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Direct feedback samples the output itself

The feedback path returns the output directly to the minus input.

V−=VoutV_- = V_{\text{out}}
Direct feedbackThe output is wired back as the feedback node.+-op amprails -12 V to 12 VVout 5 VV+ 5 VV- 5 VI+ 0 AI- 0 AVin 5 VV+ = V-follower

The follower copies the input within the rails

The input is 5 volts, so the output is also 5 volts.

Vout=V+=5 VV_{\text{out}} = V_+ = 5\ \text{V}
Voltage followerThe checked output equals the checked input.+-op amprails -12 V to 12 VVout 5 VV+ 5 VV- 5 VI+ 0 AI- 0 AVin 5 VV+ = V-follower