What will be the temperature changes affect on the emitter feedback circuit?

Explanation: Since the temperature changes I_E value, these results in the increase of feedback through R_E, which in turn reduces Ib, resulting in constant gain, even though temperature effects beta and other transistor parameters, due to the feedback these effects are neutralized.

What is emitter feedback?

Emitter feedback: A different method of introducing negative feedback into a circuit. This new feedback resistor drops voltage proportional to the emitter current through the transistor, and it does so in such a way as to oppose the input signal influence on the base-emitter junction of the transistor.

Which type of feedback is provided by base bias with emitter feedback biasing?

If an emitter resistor is added to the base-bias circuit, the result is emitter-feedback bias, as shown in Figure. The idea is to help make base bias more predictable with negative feedback, which negates any attempted change in collector current with an opposing change in base voltage.

What is the function of Re in the collector emitter feedback circuit?

2. What is the function of R_E in the collector emitter feedback circuit? Explanation: In a collector feedback circuit, the emitter resistor provides additional stability along with increasing the negative feedback sent to the collector.

Which bias is more stable?

Collector Feedback Biasing a Transistor

The DC base bias voltage is derived from the collector voltage V_C, thus providing good stability.

Emitter Feedback Bias Circuit

When the temperature is increased What happens to the collector current after feedback is given?

5. When the temperature is increased, what happens to the collector current after a feedback is given? Explanation: Before the feedback is applied, when the temperature is increased, the reverse saturation increases. The collector current also increases.

What is stability factor?

Explanation: Stability factor is defined as the rate at which collector current changes when Base to emitter voltage changes, keeping base current constant. It can also be defined as the ratio of change in collector current to change in base current when temperature changes occur.

What is the effect of emitter resistance in CE amplifier?

The aim of an AC signal amplifier circuit is to stabilise the DC biased input voltage to the amplifier and thus only amplify the required AC signal. This stabilisation is achieved by the use of an Emitter Resistance which provides the required amount of automatic biasing needed for a common emitter amplifier.

What happens to the collector current if the emitter current increases while no base voltage is applied?

Explanation: When no voltage is provided at the base then no current passes from emitter to collector, so even if very high potential difference is applied at the emitter collector junction, no current flows through it.

What is the effect of emitter bypass capacitor on frequency response?

Effect of Bypass capacitors:

At lower frequencies, bypass capacitor CE is not a short. So emitter is not at ac ground. Xc in parallel with RE creates an impedance. The signal voltage drops across this impedance reducing the circuit gain.

What are the factors that affect the bias stability of a transistor?

Factors affecting the operating point

As temperature increases, the values of I_CE, β, V_BE gets affected. So the main problem which affects the operating point is temperature. Hence operating point should be made independent of the temperature so as to achieve stability. To achieve this, biasing circuits are introduced.

What is early effect and early voltage?

The Early effect, named after its discoverer James M. Early, is the variation in the effective width of the base in a bipolar junction transistor (BJT) due to a variation in the applied base-to-collector voltage.

What are the effects on the output voltage if the collector resistance increases in a collector feedback configuration?

What are the effects on the output voltage if the Collector resistance increases in a Collector feedback configuration? Explanation: The increase in collector resistance doesn't have much impact on the output voltage since the bias voltage is kept stable by the feedback operation.

What is emitter biased circuit?

One way to bias a BJT transistor is a method called emitter bias. Emitter bias is a very good and stable way to bias transistors if both positive and negative power supplies are available. Emitter bias fluctuates very little with temperature variation and transistor replacement.

How do you calculate emitter current?

Calculate the emitter current, which is the current flowing from the emitter to ground. Use the formula Ie = (Vbb - Vbe)/[Rb/(Beta + 1) + Re] where Ie is the variable for the emitter current and Vbe is the base to emitter voltage.

What is two supply emitter bias?

The requisite forward-bias on the base-emitter is then achieved by connecting the emitter to a negative power supply. This circuit configuration is shown in Figure 5.3. 1 using an NPN device. We shall refer to this as two-supply emitter bias.

What happens to the base current if we increase the temperature?

Intrinsic semiconductor current between the collector and base increases with temperature.

Why does the collector current of a BJT in the active region increases with increasing collector voltage for a given base current?

Hello, an increase in base current means more bias to the transistor which further means collector current will also increase but till the limiting value of the transistor parameters.

What happens to the collector current when the base current increases?

As the base current increases the collector increases proprtionally till the operating point reaches the boundary between the active region and the saturation region. At this point the collector current will be equal to collector saturation current.

What is the effect of change in RS on circuit?

If the source resistance is increased, the effect will be like a voltage divider reducing the actual voltage at the amplifier input terminals. If the source resistance is increased further the overall gain will be reduced further.

Why does emitter resistor reduce gain?

If you add an emitter resistor, the base-emitter voltage does not change as much so the current change is less and therefore the gain is reduced. That is because the emitter current change causes the emitter voltage to change in the same direction as the change in base voltage, partially counteracting the effect.

Which of the following affects the input resistance of CE amplifier?

Answer. When an emitter resistance is added in a CE (Common Emitter) amplifier, its voltage gain is reduced, but the input impedance increases. Whenever bypass capacitor is connected in parallel with an emitter resistance, the voltage gain of CE amplifier increases.

What is fixed bias?

In the base circuit,

For a given transistor, V_BE does not vary significantly during use. As V_CC is of fixed value, on selection of R_B, the base current I_B is fixed. Therefore this type is called fixed bias type of circuit.

What is Q point for?

The operating point of a device, also known as a bias point, quiescent point or Q-point, is the steady-state DC voltage or current at a specified terminal of an active device such as a transistor with no input signal applied.

What is self bias circuit?

Self bias is when some parameter of transistorized circuit (voltage/current) is connected to the biasing circuit, such that the changes in transistor parameter effect it's own biasing circuit.