The purpose of capacitor between emitter to ground is to permit the transis tor to function in the depletion region without the elimination of the Q point.
The capacitor is called a bypass capacitor , it provides a low impedence path for AC emitter current to groun.
Gain in a CE configuration of a BJT is collector resistance divided by emitter resistance, subject to the limit of hFe. The emitter bypass capacitor will have lower impedance at high frequency, so the gain will be higher at higher frequency, making this a high-pass amplifier.
The emitter resistor is connected to ground(in the case of an rc coupled amplifier).Also input signal applied at the base is grounded.Then the emitter resistor forms a feedback to the input signal (through the ground return path).So emitter resistor is also called feedback resistor.
Bypass capacitors are used to bypass (shunt) unwanted signals to the ground. A common use is in power supplies where a bypass capacitor is connected in parallel with the main filter capacitor to shunt noise and other high frequency interference to ground which the main capacitor may not be able to do.
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.
The capacitor is called a bypass capacitor , it provides a low impedence path for AC emitter current to groun.
a capacitor that bypasses a BJT's emitter bias resistor so the emitter is at AC ground but has a DC bias voltage on it to set operating conditions. without the bypass, the bias would not stay constant.
It can be used as a feedback and to ground unwanted signals and frequencies
The capacitor helps to keep the quiesent point fixed. During its operation it bypasses the ac component. If the ac also flows through this emitter link then as we know by parameter equations emitter current and ce voltage changes hence varying q point.
Gain in a CE configuration of a BJT is collector resistance divided by emitter resistance, subject to the limit of hFe. The emitter bypass capacitor will have lower impedance at high frequency, so the gain will be higher at higher frequency, making this a high-pass amplifier.
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.
I think you mean a common emitter amplifier, which is an amplifier of voltage. Emitter-follower or common collector amplifiers are used to match impedances, or to amplify power or current. The emitter-follower is a type of common emitter circuit that has a resistor between the emitter and ground. The output signal is taken from the point between the emitter and its resistor.
A common emitter BJT transistor has the emitter ground. So u measure input voltage at base with respect to the ground, i.e; emitter and also u measure the output voltage at collector with respect to the ground, i.e; emitter. Hence, the emitter is common and thus the name.
Positive post of capacitor is connected to the heavy amp cable. The ground terminal (or case) of the capacitor is connected to the car's ground or a ground wire that leads to the car's chassis. That's it.
The emitter resistor is connected to ground(in the case of an rc coupled amplifier).Also input signal applied at the base is grounded.Then the emitter resistor forms a feedback to the input signal (through the ground return path).So emitter resistor is also called feedback resistor.
need to use BC107 transistor which has three terminals base, collector and emitter........ collector is connected with 6.8k ohm resistor other end of this resistor is connected with 3.7 ohm resistor and it is connected to the base of the transistor which is already connected to a capacitor of 1 micro F and a positive of function generator......and in the output side i.e in the collector and emitter side connect the 1 micro F capacitor and 10 kohm resistor and connect the CRO...... then other to the ground.......
If a circuit is grounded through a capacitor it is referred to as AC ground because ac signal can pass through the capacitor DC level is blocked