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biasing of an op amp

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samina

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can any one please tell me how a voltage divider provide biasing for an op amp.especially when both inputs are connected to a common dc source.
plis plis help me.........
 

audioguru

Well-Known Member
Most Helpful Member
Are you using the opamp as a differential amplifier?
Please attach your schematic.
 
can any one please tell me how a voltage divider provide biasing for an op amp.especially when both inputs are connected to a common dc source.
plis plis help me.........

Almost all op-amps are designed to operate off symmetrical +/- power supplies. When this is done, the inputs and output will be very close to 0Vdc. If you operate it off a + or - supply and DC ground, the output will split the voltage and be at 0.5Vdc. The inputs will also want to be at the same voltage level. Therefore, you need a voltage divider to cut the voltage in half for the input that would normally be connected to DC ground. It's preferable to use another op-amp as a voltage follower to supply that bias voltage: much less AC impedance, and a more accurate voltage since the follower is acting to correct that voltage split.

See attached for example.
 

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