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How does capacitor improves the performance of a circuit?

This depends on what kind of circuit you have. Generally, you cannot just add a capacitor to a circuit and 'improve it'. Probably, though, you mean an amplifier, anf by improve, you mean improved frequency response. In a transistor amplifier, you sometimes want increased gain at higher frequencies. By adding a capacitor from the emitter to ground, you create a low impedance path to ground for the AC signal. This lowered emitter impedance increases the gain of the amplifier, for frequencies where the capacitor looks like a low impedance, or high frequencies.


How are the capacitors treated in the dc equivalent circuit of an amplifier?

In dc equivalent circuit of an amplifier all capacitors are replaced by open circuit because capacitor block dc. As , Xc=1/2πfC We know that that frequency of dc is zero so Xc will infinite so we replace all capacitors with open circuit.


Why to short circuit capacitor in small signal analysis of BJT?

if the input signal passes through the biasing resistors, the biasing conditions get altered . To prevent this, the input signal should be directly sent to the amplifier (BJT) .Since a capacitor acts as a short circuit for ac signals,capacitors are placed both in the input side and the output side.


Design and implementation of a buffer circuit using operational amplifier?

design and implementation of a buffer circuit using operational amplifier


What is amplifier roll off?

A practical amplifier will contain several components of a "shunt" capacitance inherent in the transistor and physical wiring of the amplifier circuit. As the frequency of the input signal increases, the reactance of these shunt-capacitances will decrease until, at a frequency determined by the value of the shunt-capacitance and the circuit impedance, signal attenuation begins to take place. Thus the shunt capacitances limit the high-frequency response of the amplifier (note that the transistor itself also has inherent limits to it's high frequency amplifying capability). In the case of operational amplifiers, many operational amplifiers are internally compensated by a small capacitor (e.g. about 30pf for a 741). The internal frequency compensation capacitor prevents the operational amplifier from oscillating with resistive feedback.

Related Questions

What should be the value of capacitor at transistor amplifier circuit input?

at full input, if the transistor is working, the value of capacitor will be 0.


Resistor and capacitor built circuit for alarm switch?

I wanna use resistor , capacitor and amplifier 7173 for switch alarm circuit. How can i choice resistor and capacitor value because i wanna use 24V DC.


How does capacitor improves the performance of a circuit?

This depends on what kind of circuit you have. Generally, you cannot just add a capacitor to a circuit and 'improve it'. Probably, though, you mean an amplifier, anf by improve, you mean improved frequency response. In a transistor amplifier, you sometimes want increased gain at higher frequencies. By adding a capacitor from the emitter to ground, you create a low impedance path to ground for the AC signal. This lowered emitter impedance increases the gain of the amplifier, for frequencies where the capacitor looks like a low impedance, or high frequencies.


Why capacitor reduce gain of ce amplifier?

Where is this capacitor in the circuit?A capacitor across the emitter bias resistor actually increases the AC gain because it bypasses that resistor, by increasing the ratio of collector impedance to emitter impedance which determines the amplifier voltage gain.A capacitor across the base input resistor actually increases the AC gain because it bypasses that resistor, by decreasing the attenuation of the input signal by the input circuit network.


What is single tuned voltage amplifier?

it is a circuit consisting of a tuned circuit with a capacitor in parallel with inductor and it is connected to collector terminal in common emitter configuration,, and it is used as frequency receiver


Is capacitor a part of integrated circuit?

A small capacitor can be part of an integrated circuit.


When a capacitor is connected to a circuit, what happens to the current flow through the capacitor?

When a capacitor is connected to a circuit, the current flow through the capacitor initially increases and then decreases as the capacitor charges up.


Why does the bypass capacitor decrease the input impedance in common emitter amplifier?

You would use a supply bypass capacitor in a common collector amplifier... It's necessary, to give the positive supply rail a direct AC connection to ground. Without it, I don't think the amplifier would work properly. However, if you're using a power supply and not a battery, then chances are that it HAS a big capacitor inside it, eliminating the need for any external capacitor.


What happens when you remove capacitor in filter circuit?

The capacitors allow the signal to pass through, while 'blocking' the DC voltage level that the signal is 'riding' on. Are you asking to remove the capacitor and connect it straight through? If you had a multistage amplifier, then the DC riding voltage would try to get amplified as well, and the next stage amplifier would probably 'max out' and you'd wind up with just solid DC output, or components further along in the circuit could be damaged. If you're asking if the capacitor was taken out (like if it blew) then no signal would get through.


Why capacitor in transistor amplifier circuit at input?

Because capacitor not allow to pass dc voltage,but capacitor allow ac voltage and signal.Purpose is to block dc voltage.That is coupling condenser.


What happens to the current in a circuit as a capacitor charges?

What happens to the current in a circuit as a capacitor charges depends on the circuit. As a capacitor charges, the voltage drop across it increases. In a typical circuit with a constant voltage source and a resistor charging the capacitor, then the current in the circuit will decrease logarithmically over time as the capacitor charges, with the end result that the current is zero, and the voltage across the capacitor is the same as the voltage source.


What happens if a capacitor in an audio amplifier becomes open circuit and how does this affect the output?

Without knowing the location of the capacitor in the amplifier (which you do not give) no specific answer can be given, only possibilities assuming various locations (e.g. input coupling, power bypass, bias networks, interstage coupling, virtual grounding of shields). Each will have one or more characteristic symptoms it could produce in the output.