Output Resistance of Emitter Follower Solution

STEP 0: Pre-Calculation Summary
Formula Used
Finite Resistance = (1/Load Resistance+1/Small Signal Voltage+1/Emitter Resistance)+(1/Base Impedance+1/Signal Resistance)/(Collector Base Current Gain+1)
Rfi = (1/RL+1/Vsig+1/Re)+(1/Zbase+1/Rsig)/(β+1)
This formula uses 7 Variables
Variables Used
Finite Resistance - (Measured in Ohm) - A finite resistance simply means that the resistance in a circuit is not infinite or zero. In other words, the circuit has some amount of resistance, which can affect the behavior of the circuit.
Load Resistance - (Measured in Ohm) - Load resistance is the resistance value of load given for the network.
Small Signal Voltage - (Measured in Volt) - The Small signal voltage is a quantitative expression of the potential difference in electrical charge between two points in an electrical field.
Emitter Resistance - (Measured in Ohm) - Emitter Resistance is a dynamic resistance of the emitter-base junction diode of a transistor.
Base Impedance - (Measured in Ohm) - Base Impedance is the ratio of the base voltage to the base current. It is denoted as Zbase.
Signal Resistance - (Measured in Ohm) - Signal resistance is the resistance which is fed with the signal voltage source of an Amplifier.
Collector Base Current Gain - Collector Base Current Gain is a term used in electronic circuits to describe the maximum current that a collector-emitter junction of a transistor can tolerate without breaking down.
STEP 1: Convert Input(s) to Base Unit
Load Resistance: 1.013 Kilohm --> 1013 Ohm (Check conversion here)
Small Signal Voltage: 7.58 Volt --> 7.58 Volt No Conversion Required
Emitter Resistance: 0.067 Kilohm --> 67 Ohm (Check conversion here)
Base Impedance: 1.2E-06 Kilohm --> 0.0012 Ohm (Check conversion here)
Signal Resistance: 1.12 Kilohm --> 1120 Ohm (Check conversion here)
Collector Base Current Gain: 12 --> No Conversion Required
STEP 2: Evaluate Formula
Substituting Input Values in Formula
Rfi = (1/RL+1/Vsig+1/Re)+(1/Zbase+1/Rsig)/(β+1) --> (1/1013+1/7.58+1/67)+(1/0.0012+1/1120)/(12+1)
Evaluating ... ...
Rfi = 64.2504714452203
STEP 3: Convert Result to Output's Unit
64.2504714452203 Ohm -->0.0642504714452203 Kilohm (Check conversion here)
FINAL ANSWER
0.0642504714452203 0.06425 Kilohm <-- Finite Resistance
(Calculation completed in 00.004 seconds)

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10+ Emitter Follower Calculators

Output Resistance of Emitter Follower
Go Finite Resistance = (1/Load Resistance+1/Small Signal Voltage+1/Emitter Resistance)+(1/Base Impedance+1/Signal Resistance)/(Collector Base Current Gain+1)
Collector Current in Active Region when Transistor Acts as Amplifier
Go Collector Current = Saturation Current*e^(Voltage across Base Emitter Junction/Threshold Voltage)
Saturation Current of Emitter Follower
Go Saturation Current = Collector Current/e^(Voltage across Base Emitter Junction/Threshold Voltage)
Input Resistance of Emitter Follower
Go Input Resistance = 1/(1/Signal Resistance in Base+1/Base Resistance)
Base Resistance across Emitter follower Junction
Go Base Resistance = High Frequency Constant*Emitter Resistance
Total Emitter Resistance of Emitter Follower
Go Emitter Resistance = Base Resistance/High Frequency Constant
Output Resistance of Transistor at Intrinsic Gain
Go Finite Output Resistance = Early Voltage/Collector Current
Collector Current of Emitter Follower Transistor
Go Collector Current = Early Voltage/Finite Output Resistance
Input Resistance of Transistor Amplifier
Go Input Resistance = Amplifier Input/Input Current
Input Voltage of Emitter Follower
Go Emitter Voltage = Base Voltage-0.7

15 Multi Stage Transistor Amplifiers Calculators

Open Circuit Bipolar Cascode Voltage Gain
Go Bipolar Cascode Voltage Gain = -MOSFET Primary Transconductance*(MOSFET Secondary Transconductance*Finite Output Resistance)*(1/Finite Output Resistance of Transistor 1+1/Small Signal Input Resistance)^-1
Output Resistance of Emitter Follower
Go Finite Resistance = (1/Load Resistance+1/Small Signal Voltage+1/Emitter Resistance)+(1/Base Impedance+1/Signal Resistance)/(Collector Base Current Gain+1)
Drain Resistance of Cascode Amplifier
Go Drain Resistance = (Output Voltage Gain/(MOSFET Primary Transconductance^2*Finite Output Resistance))
Output voltage gain of MOS Cascode Amplifier
Go Output Voltage Gain = -MOSFET Primary Transconductance^2*Finite Output Resistance*Drain Resistance
Collector Current in Active Region when Transistor Acts as Amplifier
Go Collector Current = Saturation Current*e^(Voltage across Base Emitter Junction/Threshold Voltage)
Saturation Current of Emitter Follower
Go Saturation Current = Collector Current/e^(Voltage across Base Emitter Junction/Threshold Voltage)
Equivalent Resistance of Cascode Amplifier
Go Resistance between Drain and Ground = (1/Finite Output Resistance of Transistor 1+1/Input Resistance)^-1
Negative Voltage Gain of Cascode Amplifier
Go Negative Voltage Gain = -(MOSFET Primary Transconductance*Resistance between Drain and Ground)
Input Resistance of Emitter Follower
Go Input Resistance = 1/(1/Signal Resistance in Base+1/Base Resistance)
Base Resistance across Emitter follower Junction
Go Base Resistance = High Frequency Constant*Emitter Resistance
Total Emitter Resistance of Emitter Follower
Go Emitter Resistance = Base Resistance/High Frequency Constant
Output Resistance of Transistor at Intrinsic Gain
Go Finite Output Resistance = Early Voltage/Collector Current
Collector Current of Emitter Follower Transistor
Go Collector Current = Early Voltage/Finite Output Resistance
Input Resistance of Transistor Amplifier
Go Input Resistance = Amplifier Input/Input Current
Input Voltage of Emitter Follower
Go Emitter Voltage = Base Voltage-0.7

Output Resistance of Emitter Follower Formula

Finite Resistance = (1/Load Resistance+1/Small Signal Voltage+1/Emitter Resistance)+(1/Base Impedance+1/Signal Resistance)/(Collector Base Current Gain+1)
Rfi = (1/RL+1/Vsig+1/Re)+(1/Zbase+1/Rsig)/(β+1)

What is meant by emitter follower?

Emitter follower is a case of the negative current feedback circuit. This is mostly used as a last-stage amplifier in signal generator circuits. The important features of Emitter Follower are − It has high input impedance. It has low output impedance.

How to Calculate Output Resistance of Emitter Follower?

Output Resistance of Emitter Follower calculator uses Finite Resistance = (1/Load Resistance+1/Small Signal Voltage+1/Emitter Resistance)+(1/Base Impedance+1/Signal Resistance)/(Collector Base Current Gain+1) to calculate the Finite Resistance, The output resistance of emitter follower formula is a measure of how much the amplifier's output voltage changes in response to changes in the load connected to its output. Finite Resistance is denoted by Rfi symbol.

How to calculate Output Resistance of Emitter Follower using this online calculator? To use this online calculator for Output Resistance of Emitter Follower, enter Load Resistance (RL), Small Signal Voltage (Vsig), Emitter Resistance (Re), Base Impedance (Zbase), Signal Resistance (Rsig) & Collector Base Current Gain (β) and hit the calculate button. Here is how the Output Resistance of Emitter Follower calculation can be explained with given input values -> 6.4E-5 = (1/1013+1/7.58+1/67)+(1/0.0012+1/1120)/(12+1).

FAQ

What is Output Resistance of Emitter Follower?
The output resistance of emitter follower formula is a measure of how much the amplifier's output voltage changes in response to changes in the load connected to its output and is represented as Rfi = (1/RL+1/Vsig+1/Re)+(1/Zbase+1/Rsig)/(β+1) or Finite Resistance = (1/Load Resistance+1/Small Signal Voltage+1/Emitter Resistance)+(1/Base Impedance+1/Signal Resistance)/(Collector Base Current Gain+1). Load resistance is the resistance value of load given for the network, The Small signal voltage is a quantitative expression of the potential difference in electrical charge between two points in an electrical field, Emitter Resistance is a dynamic resistance of the emitter-base junction diode of a transistor, Base Impedance is the ratio of the base voltage to the base current. It is denoted as Zbase, Signal resistance is the resistance which is fed with the signal voltage source of an Amplifier & Collector Base Current Gain is a term used in electronic circuits to describe the maximum current that a collector-emitter junction of a transistor can tolerate without breaking down.
How to calculate Output Resistance of Emitter Follower?
The output resistance of emitter follower formula is a measure of how much the amplifier's output voltage changes in response to changes in the load connected to its output is calculated using Finite Resistance = (1/Load Resistance+1/Small Signal Voltage+1/Emitter Resistance)+(1/Base Impedance+1/Signal Resistance)/(Collector Base Current Gain+1). To calculate Output Resistance of Emitter Follower, you need Load Resistance (RL), Small Signal Voltage (Vsig), Emitter Resistance (Re), Base Impedance (Zbase), Signal Resistance (Rsig) & Collector Base Current Gain (β). With our tool, you need to enter the respective value for Load Resistance, Small Signal Voltage, Emitter Resistance, Base Impedance, Signal Resistance & Collector Base Current Gain and hit the calculate button. You can also select the units (if any) for Input(s) and the Output as well.
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