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Base-Current Bias (Fixed Bias)
The first biasing method, called BASE CURRENT BIAS or sometimes FIXED BIAS, was used in figure 2-12. As you recall, it consisted basically of a resistor (RB) connected between the collector supply voltage and the base. Unfortunately, this simple arrangement is quite thermally unstable. If the temperature of the transistor rises for any reason (due to a rise in ambient temperature or due to current flow through it), collector current will increase. This increase in current also causes the dc operating point, sometimes called the quiescent or static point, to move away from its desired position (level). This reaction to temperature is undesirable because it affects amplifier gain (the number of times of amplification) and could result in distortion, as you will see later in this discussion.
Self-Bias
A better method of biasing is obtained by inserting the bias resistor directly between the base and collector, as shown in figure 2-13. By tying the collector to the base in this manner, feedback voltage can be fed from the collector to the base to develop forward bias. This arrangement is called SELF-BIAS. Now, if an increase of temperature causes an increase in collector current, the collector voltage (VC) will fall because of the increase of voltage produced across the load resistor (RL). This drop in VC will be fed back to the base and will result in a decrease in the base current. The decrease in base current will oppose the original increase in collector current and tend to stabilize it. The exact opposite effect is produced when the collector current decreases.
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Which stability is greater between self bias and fixed bias?
of course stability of self bias circuit is much greater than fixed bias circuit
What are the different types of biasing?
Fixed Bias,Self Bias, Forward Bias, Reverse Bias
Advantages and disadvantage of self bias circuit?
the advantage of self bias circuit will be stable for greater range of amplitude signal than the fixed biased amplifier circuit the disadvantage is it only partially effective and therefore is only used where moderate changes in ambient temperature are expected
What are the different types of biasing technique for amplifier?
Base resistor method (or) Fixed bias methodBiasing with feedback resistor (or) Collector to base bias methodVoltage divider bias (or) Self bias
What are the types of FET biasing circuit?
Various FET biasing circuits are as follows: 1. Fixed bias 2. Self bias 3. Potential divider bias 4. Current-Source bias
What bias is called self bias?
What? Bias is a one sided opinion
What does self - enhancing bias mean?
The term self-enhancing bias is a complicated way of saying selfishness.
Which is an example of self serving bias?
the bias that we are better, smarter, and kinder than others
Why it is named as self Bias of BJT?
The Self Bias of the BJT is also called the voltage divider bias. It is called thus because it can stabilize the collector current, the base emitter voltage and the amplification factor.
What is Self serving attributional bias?
good
What is frequncy responce of common emitter amplifier?
It is the range of frequencies over which the amplifier works as designed. It is limited at the lower end by coupling capacitors in series with the signal, and at the high end by capacitance in parallel with the signal.
Why emitter bias circuit is called self bias?
emitter bias provides a feedback to the circuit so that circuit remains in linear regionn
