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Biasing Voltages and What circuits do you have to do biasing for?

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danny davis

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What circuits or tests do you have to do biasing for?

Can you give examples or list circuits that you have biased or done biasing for?

I don't get the difference between a DC voltage and a Biasing voltage, what is the difference?

When measuring voltages with a DVM meter, how do you know if its a DC voltage or a Biasing voltage? how can you tell?

I always thought a biasing voltage was when you use an oscilloscope if there was a DC offset voltage or an Waveform AC or DC riding ontop of a DC voltage that the DC voltage was the biasing voltage
 

The term "bias voltage" refers to any situation where a DC voltage is combined with a variable voltage. Your example with the oscilloscope is one such example, but there are many others. You can't tell the difference between a DC voltage and a biasing voltage with a DVM because the difference is in the purpose of the DC voltage. And you can't read "purpose" with a DVM. You have to understand the circuit to decide if something is properly described as a bias. For example a power supply produces a DC voltage, but it is not a bias voltage because it is just meant to be a single constant supply voltage. Often a bias is applied to overcome some limitation in the circuit, like a transistor that will only amplify if the base is positive with respect to the emitter.
 

But how do you know when looking at a schematic or at the nodes on the schematic that it's going to be a Biasing voltage and not a DC voltage

Using a DVM meter , it doesn't tell you if it's a biasing voltage or a normal DC voltage , so how can you know or tell?

Is every Biasing voltage a DC offset voltage with a AC or DC waveform riding on top of a DC voltage? it this the only type of biasing voltage there is

Can you guys please list circuits that you did any type of Biasing for or bench checked a Biasing voltage

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You can't tell the difference between a DC voltage and a biasing voltage with a DVM because the difference is in the purpose of the DC voltage

Why can't it tell the difference?

What do you mean by the Purpose of the DC voltage?


And you can't read "purpose" with a DVM. You have to understand the circuit to decide if something is properly described as a bias.

How do you know the PURPOSE? do you use an oscilloscope or how can you tell from the schematic?
 

Using a DVM meter , it doesn't tell you if it's a biasing voltage or a normal DC voltage , so how can you know or tell?

What is a "normal DC voltage" - do you know something about an "unnormal" dc voltage?
Each bias voltage is a dc voltage. With other words - you can use dc voltage for several purposes, and one of such a purpose is to bias a device with a suitable voltage to allow amplification around this point.
Biasing is always necessary in case you want to exploit the quasi-linear properties within a certain part of a non-linear V-I characteristic
 

Can you please list circuits that need biasing or circuits you have tested or bench checked

Give examples please
 

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