DC Amplifier

225

02:47:21

DC Amplifier are used to amplify slowly varying  signals from transducers such as thermocouples , thermistors, strain gauges, photocells,  etc.

published 9 years ago

Eribeiro

9 years ago

Can you explain the circuit or give some hints? I'm trying to make an amplifier for a 0-120mV signal. But the op amp are not capable of, due to high frequencys. I'm willing to try an audio amplifier circuit. Thanks

hurz

9 years ago

Amplify low DC voltages is more then a standard opamp circuit. Offset voltages and temperatur and aging is not that easy as here demonstarted. Suppose you have a type K temperatur sensor which gives you at 20°C only about a few 100uV and maximum maybe for 200°C 20mV. This divided into 0.1°C steps about 2000 steps or 66dB dynamic on only 0-20mV absolut voltage. Search for instrumentational amplifier and even more interesting are chopper amplifier, which convert little DC voltages into AC which then can easily amplified whitout offset problems several 40dB, 60dB or even 80dB before demodulated again to an equivalent/proportional DC voltage which can be e.g. analog digital converted. As I said this topic is interesting ;-)

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