 # What Is Current Gain In A Transistor?

## How do you gain dB?

Gain is defined as the ratio of the output power to the input power in dB.

Assume that the input power is 10 mW (+10 dBm) and the output power is 1 W (1000 mW, +30 dBm).

The ratio will be 1000/10 = 100, and the gain will be 10 * log 100 = 20 dB..

## How do I convert CMRR to dB?

Common Mode Rejection Ratio (CMRR) and The Operational AmplifierCMMR = Differential mode gain / Common-mode gain.CMRR = 20log|Ao/Ac| dB.PSRR= 20log|ΔVDc/ΔVio| dB.Error (RTI) = Vcm / CMRR = Vin / CMRR.Vout = [1 + R2/R1] [ Vin + Vin/ CMRR]Error (RTO) = [1+R2/R1] [Vin/CMRR]ΔVout = ΔVin / CMRR (1 + R2/R1)

## Why is VBE 0.7 V?

For an unbiased transistor, considering only the BE junction which is a pn junction diode, 0.7V is the potential barrier. In an npn transistor base is positive(p) and emitter is negative(n). … But in a pnp transistor the base is negative(n) and emitter is positive(p) so the vbe=-0.7V.

## What is current gain and voltage gain?

Discussion of Gain and Amplification Logic circuits need both voltage and current gain; voltage gain is required to achieve full regeneration of the logic levels after each logic operation, while the current gain sets an upper limit to the fan-out of the logic gate.

## Why current gain is important parameter in BJT?

Although other parameters of these semiconductor devices are also important, the current gain is particularly key because the bipolar transistor is a current operated device. … When designing any transistor circuit, it is necessary to ensure there is sufficient gain to enable the circuit to operate correctly.

## 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. Set Vbe to 0.7 volts, which is the standard for most transistor circuits.

## What is 3dB gain?

The frequency response of a device or a circuit describes its operation over a specified range of signal frequencies by showing how its gain, or the amount of signal it lets through changes with frequency. … These half power points corresponds to a fall in gain of 3dB (0.7071) relative to its maximum dB value.

## What is small signal gain?

Small signal gain is the gain in the amplifier’s linear region of operation. This is typically measured at a constant input power over a swept frequency. Gain flatness is the measure of the variation of gain over a specified frequency range.

## How many dB is a watt?

0 dBWDefinition: dBW means dB relative to 1 watt, so 0 dBW = 1 watt, -3 dBW = half watt. +3dBW = 2 watts etc. Definition: dBm means dB relative to 1 milliwatt, so 0 dBm = 1 milliwatt (one thousandth of 1 watt or 0.001 watt).

## What is the unit of current gain?

Current gain In the bipolar transistor example, it is the ratio of the output current to the input current, both measured in amperes. In the case of other devices, the gain will have a value in SI units.

## What is gain formula?

Basic Definitions and Formulas Formula: Profit or Gain = S.P. – C.P. Loss: If the selling price is less than the cost price, the difference between them is the loss incurred.

## What is 0 dB gain?

The amplification factor, also called gain , is the extent to which an analog amplifier boosts the strength of a signal . … If the output-to-input signal power ratio is 1:1, then the amplification factor is 0 dB. Power amplifiers typically have gain figures from a few decibels up to about 20 dB.

## How do transistors amplify current?

A transistor acts as an amplifier by raising the strength of a weak signal. The DC bias voltage applied to the emitter base junction, makes it remain in forward biased condition. This forward bias is maintained regardless of the polarity of the signal.

## How does current flow in a transistor?

The NPN transistor is designed to pass electrons from the emitter to the collector (so conventional current flows from collector to emitter). … The base still controls current flow, but that current flows in the opposite direction — from emitter to collector.

## How do you get a percentage of something?

Find the percentage of one number in relation to another with the formula Percentage = (number you want to find the percentage for ÷ total) × 100. Move the decimal point two places to the right to convert from a decimal to a percentage, and two places to the left to convert from a percentage to a decimal.

## Can you have negative gain?

Negative gain means the output is inverted from the input. For the gain to be negative, the output would have to go down when the input goes up, which is clearly not happening in your case.

## What is CE configuration?

Definition: The configuration in which the emitter is connected between the collector and base is known as a common emitter configuration. The input circuit is connected between emitter and base, and the output circuit is taken from the collector and emitter.