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What does bias mean in a valve--tube-- radio receiver circuit?
Wiki User
∙ 13y ago
Like many electronic devices, tubes (aka valves) are closer to linear in certain operating ranges--meaning the output is a scaled version of the input when operating in the linear region.
However, these linear regions are not typically at zero volts. So a DC bias is added to the AC input signal, shifting the signal into the linear region of the device. The DC bias can be removed from the output, leaving the amplified signal. Essentially the bias shifts the "zero" point for the signal to match the amplifier characteristics.
Choosing bias is an important consideration in amplifier design. Amplifiers are designated by a "class" according to their bias--class A, class B, class AB, class C (there are other classes but they aren't used with tubes). Because the bias signal is the zero signal input, the bias determines how much power the tube uses when idle. For example, a class A amplifier is biased to the middle of the tube operating range so it uses about 50% power when idle, which is wasteful and makes a lot of heat.
Wiki User
∙ 13y ago
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Why should a JFET be operated with only reverse bias on the gate source?
What is the venin and norton equivalent circuit comment?Read more: What_is_the_venin_and_norton_equivalent_circuit_comment
What is depletion mosfet?
A depletion mode MOSFET is a FET that is on with no gate bias, and requires a negative bias (with respect to the source) to stop conducting. The channel is normally conductive and with a negative gate bias the channel becomes "depleted" of charge carriers, hence the name depletion mode MOSFET. This is contrary to enhancement type MOSFET's that are non conductive with zero volts gate bias and become conductive when there is a positive bias on their gate.
Why is it important for judges to be free from bias?
So as to deliver a fair and impartial trial. Bias would militate against delivering impartiality.
What blocks current flow?
Resistors "resist" current flow. The ultimate "blocking" resistor is an open circuit, having a resistance of infinity (for all practical purposes) ohms.Capacitors also resist a change in voltage drop. For the case of a DC circuit, a capacitor, after reaching equilibrium, will present a DC resistance of infinity. For the case of the AC circuit, a capacitor will allow the AC signal to pass, while blocking any DC bias that might be present.So, resistors and, in the DC case, capacitors, block current flow.
The overwhelming bias of the news media today is neither liberal nor conservative but?
There are few who would argue the bias of the media is liberal. Overwhelmingly.
Why emitter bias circuit is called self bias circuit?
emitter bias provides a feedback to the circuit so that circuit remains in linear regionn
Why emitter bias circuit is called self bias?
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
How is automatic gain control bias voltage developed in a valve superhet radio reciver circuit?
The signal is changed to dc in the AGC circuit to change the gain. A weak signal will increase gain.
What is the purpose of a capacitor in a radio?
There are many uses of a capacitor in a radio...Combined with a resistor or inductor as part of a tuned circuit or filter.Used between stages of amplification or processing where DC bias needs to be removed.Used in the power supply to create stable DC.
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
