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What should be the value of capacitor at transistor amplifier circuit input?
Wiki User
∙ 11y ago
at full input, if the transistor is working, the value of capacitor will be 0.
Wiki User
∙ 11y ago
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Should you worry about capacitor lead length in a circuit?
Capacitor lead length is a consideration in a circuit when the frequency involved is sufficient the make the parasitic capacitance and inductance of the leads important.
Why capacitor behave as open circuit against alternating current?
Capacitors store electrical charge. Imagine we have a capacitor. At time 0 seconds we connect a DC voltage across the capacitor - immediately as the voltage is connected the capacitor is at 0 volts and the maximum current (relative to the circuit resistance) flows. At this extreme the capacitor can be treated as a short circuit, so for high frequency AC volts we should treat a capacitor as being a short circuit. As time passes the current in the circuit will go down and the voltage of the capacitor will go up - this is because as the capacitor gains more charge it gains more voltage, lowering the voltage across any resistance in the circuit consequently lowering the current in the circuit. When the capacitor is virtually full no current will flow at all and the voltage across the capacitor will equal the DC source voltage. At this extreme the capacitor can be treated as an open circuit, so for low frequency AC (allowing the capacitor to fill up before the current alternates) we can treat the capacitor as being an open circuit. Technically, it is not an open/closed circuit when it comes to AC because the capacitance will results in a signal lag or lead. However, if the frequency is low/high enough the lag/lead is often negligable.
Why you use capacitor before connecting transtitor?
Before connecting to the transistor we use a capacitor becausefor the transistor to amplify we should first apply DC biasing so that we can set an operating point to itso once the transistor is biased DC currents flow in the whole circuitryAll the AC signal source are shorts to the DC currents so we employ capacitor for two reasons1.As capacitor blocks DC and allows AC it is connected for not moving the DC operating point of the transistor and making it fixed since if any small DC part arises in the signal it leads to the change of operating point and our amplification procees gets affected2.To block the already present DC currents in the circuitry for not getting away and making it fixed
Why is gain affected when the bypass capacitor is open?
Applied input signal at the base of the amplifier appears across the emitter resistor (RE) due to inter electrode capacitance so it should be bypassed the emitter resistor (RE) through the bypass capacitor (CB). unbypassed signal will be amplified (common emitter amplifier) and reverse back from the emitter to the collector through the base, amplified signal from the emitter to the collector (common emitter amplifier) is 1800 out of phase to the amplified signal from the base to the collector (common base amplifier), so reduced the gain.
What is the purpose of the capacitors at the input and output signals?
There are two primary uses of a capacitor in the biasing of a transistor. One is to isolate the DC component of the input or output signal from the input or output of the transistor. This is often done in audio applications where the input signal is centered around ground reference, but the base is biased at 0.7 volts. Similarly, the collector is biased away from ground, but the signal needs to be shifted back to ground reference. The second is to change the gain as a function of frequency. Depending on where the capacitor is located in the circuit, the capacitative reactance as a function of frequency can add to or subtract from the bias point and/or gain of the circuit. Usually, this capacitor would be located on output side, along with the emitter or collector resistors.
How should the two transistor junctions be biased for proper transistor amplifier operation?
Emitter-Base junction should be forward biased.Collector-Base junction should be reverse biased.
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.
How do you set up an RC circuit that will keep a 12V lamp on for 4 seconds after depressing the switch?
Use a transistor to drive a small relay. When the switch is pressed it should turn on the transistor and at the same time charge a small capacitor. Discharge the capacitor over 4 second time period with a resistor. You will have to experiment with resistors to find one that gives an acceptable discharge rate. Note, if the 12V lamp is running DC you can drive it directly with the transistor and forget about the relay.
When working on a capacitor the connection points should be?
That depends on the circuit you are modifying.
Should you worry about capacitor lead length in a circuit?
Capacitor lead length is a consideration in a circuit when the frequency involved is sufficient the make the parasitic capacitance and inductance of the leads important.
What are the steps behind installing a car audio capacitor?
First, the capacitor must be charged. Use a voltmeter, and when it reaches 12 volts, the capacitor is charged. The capacitor should then be installed near the car audio amplifier. Keep the negative wire attached to the battery. Then, a ground wire from the negative post on the capacitor to the car's chassis on the chassis's bare metal ground point. Next, the power wire needs to be disconnected from the amplifier's power input. Connect the wire to the positive post on the capacitor. A new power wire needs to be connected from the capacitor's positive post to the amplifier's power input. Install a 16 gauge wire from the capacitor's remote turn-on post to the amplifier's remote input. Then disconnect the negative wire from the battery.
Which electric element should be used so as to open the closed electric circuit?
A switch, circuit breaker, fuse, or switching transistor can do that.
Why capacitor behave as open circuit against alternating current?
Capacitors store electrical charge. Imagine we have a capacitor. At time 0 seconds we connect a DC voltage across the capacitor - immediately as the voltage is connected the capacitor is at 0 volts and the maximum current (relative to the circuit resistance) flows. At this extreme the capacitor can be treated as a short circuit, so for high frequency AC volts we should treat a capacitor as being a short circuit. As time passes the current in the circuit will go down and the voltage of the capacitor will go up - this is because as the capacitor gains more charge it gains more voltage, lowering the voltage across any resistance in the circuit consequently lowering the current in the circuit. When the capacitor is virtually full no current will flow at all and the voltage across the capacitor will equal the DC source voltage. At this extreme the capacitor can be treated as an open circuit, so for low frequency AC (allowing the capacitor to fill up before the current alternates) we can treat the capacitor as being an open circuit. Technically, it is not an open/closed circuit when it comes to AC because the capacitance will results in a signal lag or lead. However, if the frequency is low/high enough the lag/lead is often negligable.
What does the volt on a capacitor mean?
the voltage number on the capacitor indicates that the capacitor can with stand to that particular voltage across it.generally during design, the value of capacitor will be selected in such a way that this voltage rating should be double than what really we get in the circuit
Why clipping should be accounted for in designing amplifier circuit?
A: If an amplifier can be subjected to either input or output overdrive then clipping of both is desirable to insure safety margin and insure amplifier recovery in a minimum time
Why you use capacitor before connecting transtitor?
Before connecting to the transistor we use a capacitor becausefor the transistor to amplify we should first apply DC biasing so that we can set an operating point to itso once the transistor is biased DC currents flow in the whole circuitryAll the AC signal source are shorts to the DC currents so we employ capacitor for two reasons1.As capacitor blocks DC and allows AC it is connected for not moving the DC operating point of the transistor and making it fixed since if any small DC part arises in the signal it leads to the change of operating point and our amplification procees gets affected2.To block the already present DC currents in the circuitry for not getting away and making it fixed
Why is gain affected when the bypass capacitor is open?
Applied input signal at the base of the amplifier appears across the emitter resistor (RE) due to inter electrode capacitance so it should be bypassed the emitter resistor (RE) through the bypass capacitor (CB). unbypassed signal will be amplified (common emitter amplifier) and reverse back from the emitter to the collector through the base, amplified signal from the emitter to the collector (common emitter amplifier) is 1800 out of phase to the amplified signal from the base to the collector (common base amplifier), so reduced the gain.
