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To severely oversimplify it: to set the operating pointof the circuit.
In more detail, amplifying devices like vacuum tubes and transistors are inherently nonlinear and only amplify over a limited range of voltages and currents. An operating pointmust be selected on the device's response curve and then bias set in the circuit to maintain the device at that operating point to make the circuit do what is desired.
- for an amplifier with good linearity (class A) the selected operating point is in the middle of the most linear part of the curve
- for a high power amplifier (class B push-pull) the selected operating point is at cutoff, with one device amplifying while the other rests then on the next half cycle they switch
- for digital circuits the selected operating point is usually well beyond cutoff and gain is set very high so as soon as the device is driven out of cutoff by a signal it saturates
- etc.
What else can I help you with?
Why emitter bias circuit is called self bias circuit?
emitter bias provides a feedback to the circuit so that circuit remains in linear regionn
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 is a fixed bias circuit?
it is a switching device that need a current..so u will need a resistor to open the switch..
Why emitter bias circuit is called self bias?
The emitter bias circuit is called self-bias because the bias voltage across the emitter-resistor is based on the transistor's own characteristics. The bias voltage adjusts itself based on the varying collector current to stabilize the operating point of the transistor. It is a self-adjusting mechanism that helps maintain a stable bias point for the transistor.
What are the applications of fixed bias circuit?
low input impedance
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 are the advantages of self bias on other bias?
1. stability factor s for voltage divider or self bias is less as compared to other biasing circuits . So this circuit is more stable and hence it is most commonly used. 2. this circuit is used where only moderate changes in ambient temperature are expected 3. the bias automatically adjusts to any variations in the circuit. by prerita agarwal
What are the applications of fixed bias amplifier circuit?
low input impedance
What are the characteristics of fixed bias?
It is a bias of a fixed voltage supplied by a separate low-power bias supply. Early radios used a 9 v tapped bias battery. In some amplifiers fixed bias can be dispensed with and the bias voltage is derived from one of the currents in the circuit.
What is the difference between constant current bias and current mirror circuit?
current mirror circuit produce more stability as compared to biased circuit.
Why fixed bias circuit is called so?
because we are not varying the biasing voltage
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
