S sagh Member Mar 29, 2015 #1 Can anyone tell me Why a voltage amplifier should have a high input resistance?
Nigel Goodwin Super Moderator Most Helpful Member Mar 29, 2015 #2 sagh said: Can anyone tell me Why a voltage amplifier should have a high input resistance? Click to expand... No reason it has to, and in many cases it certainly won't. But for a perfect (theoretical) 'voltage' amplifier it would need to have infinite input impedance so it draws zero current - but real life doesn't work like that.
sagh said: Can anyone tell me Why a voltage amplifier should have a high input resistance? Click to expand... No reason it has to, and in many cases it certainly won't. But for a perfect (theoretical) 'voltage' amplifier it would need to have infinite input impedance so it draws zero current - but real life doesn't work like that.
MikeMl Well-Known Member Most Helpful Member Mar 29, 2015 #3 Depends entirely on what is supplying the input to the amplifier. Some signal sources require a high input impedance so that the amplifier doesn't load the source (e.g. Electret mic)... Others want a specified load impedance, so the amplifier is designed to provide that specific impedance... Still others are near a pure voltage source, so don't care what the input impedance of the amplifier is...
Depends entirely on what is supplying the input to the amplifier. Some signal sources require a high input impedance so that the amplifier doesn't load the source (e.g. Electret mic)... Others want a specified load impedance, so the amplifier is designed to provide that specific impedance... Still others are near a pure voltage source, so don't care what the input impedance of the amplifier is...