Non-Inverting Gain and Followers

Non-Inverting Gain Adds One

the divider samples output

A non-inverting amplifier uses a feedback divider, so its gain is one plus a ratio. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

The feedback divider samples the output

The feedback divider uses 3 ohms to ground and 6 ohms to the output.

RfRg=6 ohm3 ohm=2\frac{R_f}{R_g} = \frac{6\ \text{ohm}}{3\ \text{ohm}} = 2
Feedback dividerThe inverting input is the checked divider node.+-op amprails -12 V to 12 VVout 6 VV+ 2 VV- 2 VI+ 0 AI- 0 AVin 2 VRg 3 ohmRf 6 ohmV+ = V-noninverting

The non-inverting gain adds one

The gain is one plus the resistor ratio, so 2 volts becomes 6 volts.

Vout=(1+2)⋅2 V=6 VV_{\text{out}} = (1+2)\cdot 2\ \text{V} = 6\ \text{V}
Non-inverting gainThe output makes the divider node equal the input.+-op amprails -12 V to 12 VVout 6 VV+ 2 VV- 2 VI+ 0 AI- 0 AVin 2 VRg 3 ohmRf 6 ohmV+ = V-noninverting