Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
biasing means to set something up. like for instance a transistor in its own is of no use. it cant do amplification, switching, controling bla bla bla. but when we bias it we can make it an amplifier, switch, control element.....
biasing is done by setting up voltages at the pins of the transistor. the biasing determines the way the transistor will behave.
In general it means adding an additional voltage or signal. In analog tape recorders, a large amplitude ac signal that is out of band is added to the signal being recorded to make the recording process work better. In active devices a DC signal is added because electron devices operate on only one polarity. The combination of the DC bias and the desired AC signal add up to different levels of one polarity.
BIASING means : Adjusting or setting the PROPER OPERATING LEVEL of an ACTIVE device ..It can be current or VOLTAGE
one example :
Suppopse you have a very small input signal to be amplified by a transistor .Let's say of .001 volt .. But to make work the base of that transistor you need at least 0.3 Volt .. so is clear that your signal is to WEAK to ACTIVATE the transistor so here is necesseary to apply some bias to ACTIVATE the TRANSISTOR and on top of that BIASING VOLYAGE you will ADD the INPUT SIGNAL .. Now the transistor is ACTIVE because of the bias voltage wich is a FIXED amount so the transistor OUTPUT will only vary in FUNCTION of the INPUT SIGNAL .. At the transistor OUTPUT you will add a CAPACITOR .. and get just the AMPLIFIED COPY of the INPUT .. the CAP will remove the OUTPUT VOLTAGE originated by the BIASING at the INPUT ..
Hi
When people talk about "biasing" an amplifier, they are referring to setting the "idle", or quiescent, current in the power output tubes. All tubes must be biased, both preamp and output tubes, but it is not always clear whether or not the bias needs to be adjusted when changing tubes
Verb 1. bias - influence in an unfair way; "you are biasing my choice by telling me yours"
prejudice, prepossess - influence (somebody's) opinion in advance
handicap - attempt to forecast the winner (especially in a horse race) and assign odds for or against a contestant
2. bias - cause to be biased
predetermine
prejudice, prepossess - influence (somebody's) opinion in advance
slant, weight, angle - present with a bias; "He biased his presentation so as to please the share holders"
Biasing in the electrical or electronic sense is much similar to the English meaning of the word 'bias' - to influence in an unfair way. A common example is the transistor which we use to amplify an AC signal. To make the transisitor work, we will need to apply a DC to turn it on. Biasing in this sense is to use a DC to influence the AC signal such that it is prejudiced into the region of operation of the transistor.
One commonly overlooked example is the polarised electrolytic capacitor. If we just pass an AC through, one half of the cycle will be distorted because the polarised capacitor works only for one direction of current flow. So this AC signal should also be influenced in a way such that it becomes unbalanced with a DC offset such that the AC signal can pass through the capacitor without distortion.
An example cited by flatulent is a classical example of biasing with another AC signal. To overcome magnetic hysteresis, analog tape heads for recording are biased with a high frequency AC signal. So the original audio signal is added with a high frequency signal that is used to overcome the hysteresis while the audio signal gets recorded onto the tape.
I see a lot of people do have trouble with biasing especially with transistors.
When you use a curve tracer(for a diode or transistor) to measure current-voltage curves you will establish a point where you want to operate the device.
For diodes is not a problem that much the biasing but for the transistors you are worried. You find the device's characteristics and select a point you will operate it.
Now for a BJT for example current-voltage curves from curve-tracer also it shall tell you what is base current you need to supply in order to get corresponding level of collector you did choose the point of operating the device.
Knowing this you design a network later. This is network is called bias network or "the bias".
Remember rule of thumb: Solid-State devices are not energy sources so you need a DC(most likely) source in this bias network to also drive the device. You dont do that device is not going to do what you thought so.
biasing means applying some dc voltage to BJT/MOSFET so that it can be made to operate in desired region of operation for desired functionality........
BIASING MEANS TO SIMPLY TO APPLY VOLTAGE TO A DEVICE IN ELECTRONICS THIS TERM IS OFTEN USED FOR FET AND BJT THEY ARE BIASED IN FORWARD AND REVERSE MODE
Biasing means adding some dc voltage to the component such that its operating point is in linear region. then the device can be operated inlinear device...
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.