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What is the operating point?

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KeigoH

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I can't imagine this...
 

When one uses transistors this is the DC bias applied to the transistor. This is done in order to place the transistor on a favourable location on the operating graphs (check the datasheet)

Cheers
Slayer
 

The operating point of the transistor is the point of DC bias that allows full AC swing, thereby maximizing stage amplification.
 

The operating point is also known as the quiescent point, the Q-Point. In normal operation, a circuit or system of circuits has inputs and outputs; hence, the circuit or system of circuits isn't at rest. The Q-Point, simply put, is the circuit (or system's) state of rest, where inputs that cause change have been removed.

As an example, say you were looking at an audio amplifier. The Q-Point of the amp is the current and voltage values at all points in the amp with 1) no input signal and the input of the amp only sourced with the series resistance of its driver and 2) the output of the amp looking at its load. These two conditions will put the amp at rest.

How the Q-Point relates to a digital circuit, I'm not sure, as the inputs of digital circuits are either high or low. I'd guess that'd give two Q-Points, one for high input and one for low input.
 

The operating point of the transistor is the point of DC bias that allows full AC swing, thereby maximizing stage amplification
Click to expand...

operating pint means the v,i values that make the transistor operate in its linear region.
Click to expand...

NOT necessarily. The V and I DC bias values that a transistor is biased at, is it's operating point. The transistor may or may not be in the linear region, neither is it's necessary for it to allow full AC swing.

you might have heard people say :D ... "a class C amplifier has it operating point below cut-off.... a class B amplifier has its operating point at cutoff.... a class A amplifier has it operating point at the middle of the operating range (cutoff to saturation in the case of a BJT)....
 

hi KeigoH

lets imagin:
one worker that work in a bulding, have a work point that this point is "its operating point". likely in electronic (and other science), each system has an operating point that your system work around this.

with best regards, Mostafa
 

Without the concept of Operating point the active devices like transistors cant have its working proper
 

Hi,
Operating point is the dc voltage at which the MOS transistor is working.
This decides in which region your transistor is working. In analog design using MOS transistor the transistors should be in Saturation region.
You find the operating point by the load line concept .

Thanks
Shaikh Sarfraz
 

In electronics, a bias point, also known a quiescent point or a operating point, is a dc voltage which, applied to a device, causes it to operate in a certain desired fashion. The term is normally used in connection with devices such as transistors and diodes which are used in amplification or rectification.

For example, for Bipolar Junction Transistors the bias point would keep the transistor operating in the active mode, drawing a dc current. A small signal is then applied on top of this bias voltage, thereby either modulating or switching the current, depending on the design of the circuit. The input dc voltage is chosen to satisfy the required large signal parameters.
[edit]

Sources

* Sedra, Adel; Smith, Kenneth (2004). Microelectonic Circuits. Oxford University Press. ISBN 0-19-514251-9.
Click to expand...
 

in many cases when you deel with ac signal you need to choose a dc voltage or current that has best parameters or charachterstics for your application and the ac signal alternates around it, that dc point we call it operating point.
regards
 

for analog design MOSFETs are required to be in saturation region, because here the amplification is faithful and linear. but this region is very small. so the input signal must be within this region. usually the input is apllied so that its variation is within this range. the point around which the input is applied is known as the operating point. this is usually done by superimposing it on a DC signal with a voltage equivalent to the operating point.
 

hi

the operating point differs from circuit to another accordind to the required specs. and so there is no single Q point .


regards
 

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