Emitter Resistance of BJT Calculator

✖Small signal is an AC signal (more technically, a signal having zero average value) superimposed on a bias signal (or superimposed on a DC constant signal).ⓘ Small Signal [V_ss]			+10% -10%
✖Signal current is the current in the amplified output current of a transistor.ⓘ Signal Current [i_si]			+10% -10%

✖Emitter Resistance is a dynamic resistance of the emitter-base junction diode of a transistor.ⓘ Emitter Resistance of BJT [R_e]

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Emitter Resistance of BJT Solution

STEP 0: Pre-Calculation Summary

Formula Used

Emitter Resistance = Small Signal/Signal Current
R_e = V_ss/i_si
This formula uses 3 Variables

Variables Used

Emitter Resistance - (Measured in Ohm) - Emitter Resistance is a dynamic resistance of the emitter-base junction diode of a transistor.
Small Signal - (Measured in Volt) - Small signal is an AC signal (more technically, a signal having zero average value) superimposed on a bias signal (or superimposed on a DC constant signal).
Signal Current - (Measured in Ampere) - Signal current is the current in the amplified output current of a transistor.

STEP 1: Convert Input(s) to Base Unit

Small Signal: 3.2 Volt --> 3.2 Volt No Conversion Required
Signal Current: 2.65 Milliampere --> 0.00265 Ampere (Check conversion here)

STEP 2: Evaluate Formula

Substituting Input Values in Formula

R_e = V_ss/i_si --> 3.2/0.00265

Evaluating ... ...

R_e = 1207.54716981132

STEP 3: Convert Result to Output's Unit

1207.54716981132 Ohm -->1.20754716981132 Kilohm (Check conversion here)

FINAL ANSWER

1.20754716981132 ≈ 1.207547 Kilohm <-- Emitter Resistance

(Calculation completed in 00.004 seconds)

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Created by Payal Priya

Birsa Institute of Technology (BIT), Sindri

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Vishwakarma Government Engineering College (VGEC), Ahmedabad

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Small-Signal Input Resistance between Base and Emitter

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Emitter Resistance of BJT Formula

LaTeX Go

Emitter Resistance = Small Signal/Signal Current
R_e = V_ss/i_si

Why input resistance of a transistor is low?

While using a transistor, the emitter-base junction is always forward biased and the collector-base junction is always reverse-biased. Due to it, a small change in emitter current. This means that a small signal voltage variation at the input of the transistor produces a large emitter current variation. This showed that the input resistance of a transistor is low. Since the collector is reverse-biased, it collects all the charge carriers which diffuse into it, through the base. Due to it, a very large change in collector voltage shows only a small change in the collector current. This shows that the output resistance of the transistor is high.

How to Calculate Emitter Resistance of BJT?

Emitter Resistance of BJT calculator uses Emitter Resistance = Small Signal/Signal Current to calculate the Emitter Resistance, Emitter resistance of BJT suggests that for a small signal, the transistor behaves as a voltage-controlled current source. The input port of the controlled current source is between base and emitter and the output port is in between collector and emitter. Emitter Resistance is denoted by R_e symbol.

How to calculate Emitter Resistance of BJT using this online calculator? To use this online calculator for Emitter Resistance of BJT, enter Small Signal (V_ss) & Signal Current (i_si) and hit the calculate button. Here is how the Emitter Resistance of BJT calculation can be explained with given input values -> 0.001208 = 3.2/0.00265.

FAQ

What is Emitter Resistance of BJT?

Emitter resistance of BJT suggests that for a small signal, the transistor behaves as a voltage-controlled current source. The input port of the controlled current source is between base and emitter and the output port is in between collector and emitter and is represented as R_e = V_ss/i_si or Emitter Resistance = Small Signal/Signal Current. Small signal is an AC signal (more technically, a signal having zero average value) superimposed on a bias signal (or superimposed on a DC constant signal) & Signal current is the current in the amplified output current of a transistor.

How to calculate Emitter Resistance of BJT?

Emitter resistance of BJT suggests that for a small signal, the transistor behaves as a voltage-controlled current source. The input port of the controlled current source is between base and emitter and the output port is in between collector and emitter is calculated using Emitter Resistance = Small Signal/Signal Current. To calculate Emitter Resistance of BJT, you need Small Signal (V_ss) & Signal Current (i_si). With our tool, you need to enter the respective value for Small Signal & Signal Current and hit the calculate button. You can also select the units (if any) for Input(s) and the Output as well.

How many ways are there to calculate Emitter Resistance?

In this formula, Emitter Resistance uses Small Signal & Signal Current. We can use 2 other way(s) to calculate the same, which is/are as follows -

Emitter Resistance = Threshold Voltage/Emitter Current
Emitter Resistance = Threshold Voltage/Emitter Current

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