Amplifier Selector

174

03:36:05

This circuit allows to select between a negative or positive amplifier circuit based on the switch state.

Often used in DMMs to change the sign of the input voltage.

published 11 years ago

hurz

11 years ago

To change the sign of a DMM display it just has to invert the display logic and not the analog input signal. Anyway, never use an OpAmp with positive feedback only, if you expect a linear behaviour. Increase the input voltage above 15V and try to go back to 9V and watch the output voltage! Solution, flip plus and minus input. Keep it up.

lorki97

11 years ago

Yeah I found out I forgot to swap them right after I finished the circuit.

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