Inverting amp with T feedback
6 parts
A gain of −70 from a 10 kΩ input resistor normally wants a 700 kΩ feedback resistor. Split the feedback into a T instead — two moderate resistors in line, with a small one down to ground between them — and the same gain comes out of parts no larger than 200 kΩ. The grounded leg steals part of the feedback current, so the far resistor has to swing much harder to balance the summing junction, and that extra swing is the extra gain.
- V1 100mV·1kHz
- R1 10kΩ
- R2 100kΩ
- R3 50kΩ
- R4 200kΩ
- OP1
