Emitter Resistance in Widlar Current Source Solution

STEP 0: Pre-Calculation Summary
Formula Used
Emitter Resistance = (Threshold Voltage/Output Current)*log10(Reference Current/Output Current)
Re = (Vth/Io)*log10(Iref/Io)
This formula uses 1 Functions, 4 Variables
Functions Used
log10 - The common logarithm, also known as the base-10 logarithm or the decimal logarithm, is a mathematical function that is the inverse of the exponential function., log10(Number)
Variables Used
Emitter Resistance - (Measured in Ohm) - Emitter Resistance is the emitter-degeneration resistance of the emitter-base junction diode of a transistor.
Threshold Voltage - (Measured in Volt) - Threshold voltage of transistor is the minimum gate to source voltage that is needed to create a conducting path between the source and drain terminals.
Output Current - (Measured in Ampere) - Output Current is the current the amplifier draws from the signal source.
Reference Current - (Measured in Ampere) - A reference current is just a stable source of current that does not fluctuate over temperature, supply voltages or loads.
STEP 1: Convert Input(s) to Base Unit
Threshold Voltage: 25 Volt --> 25 Volt No Conversion Required
Output Current: 5 Milliampere --> 0.005 Ampere (Check conversion ​here)
Reference Current: 7.6 Milliampere --> 0.0076 Ampere (Check conversion ​here)
STEP 2: Evaluate Formula
Substituting Input Values in Formula
Re = (Vth/Io)*log10(Iref/Io) --> (25/0.005)*log10(0.0076/0.005)
Evaluating ... ...
Re = 909.217939723863
STEP 3: Convert Result to Output's Unit
909.217939723863 Ohm -->0.909217939723863 Kilohm (Check conversion ​here)
FINAL ANSWER
0.909217939723863 0.909218 Kilohm <-- Emitter Resistance
(Calculation completed in 00.020 seconds)

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Emitter Resistance in Widlar Current Source Formula

​LaTeX ​Go
Emitter Resistance = (Threshold Voltage/Output Current)*log10(Reference Current/Output Current)
Re = (Vth/Io)*log10(Iref/Io)

What is a Widlar Current Source?

A Widlar current source is a modification of the basic two-transistor current mirror that incorporates an emitter degeneration resistor for only the output transistor, enabling the current source to generate low currents using only moderate resistor values.

How to Calculate Emitter Resistance in Widlar Current Source?

Emitter Resistance in Widlar Current Source calculator uses Emitter Resistance = (Threshold Voltage/Output Current)*log10(Reference Current/Output Current) to calculate the Emitter Resistance, The Emitter resistance in Widlar Current Source formula is defined as the opposition offered in the emitter region of the Widlar Current Source. Emitter Resistance is denoted by Re symbol.

How to calculate Emitter Resistance in Widlar Current Source using this online calculator? To use this online calculator for Emitter Resistance in Widlar Current Source, enter Threshold Voltage (Vth), Output Current (Io) & Reference Current (Iref) and hit the calculate button. Here is how the Emitter Resistance in Widlar Current Source calculation can be explained with given input values -> 0.000909 = (25/0.005)*log10(0.0076/0.005).

FAQ

What is Emitter Resistance in Widlar Current Source?
The Emitter resistance in Widlar Current Source formula is defined as the opposition offered in the emitter region of the Widlar Current Source and is represented as Re = (Vth/Io)*log10(Iref/Io) or Emitter Resistance = (Threshold Voltage/Output Current)*log10(Reference Current/Output Current). Threshold voltage of transistor is the minimum gate to source voltage that is needed to create a conducting path between the source and drain terminals, Output Current is the current the amplifier draws from the signal source & A reference current is just a stable source of current that does not fluctuate over temperature, supply voltages or loads.
How to calculate Emitter Resistance in Widlar Current Source?
The Emitter resistance in Widlar Current Source formula is defined as the opposition offered in the emitter region of the Widlar Current Source is calculated using Emitter Resistance = (Threshold Voltage/Output Current)*log10(Reference Current/Output Current). To calculate Emitter Resistance in Widlar Current Source, you need Threshold Voltage (Vth), Output Current (Io) & Reference Current (Iref). With our tool, you need to enter the respective value for Threshold Voltage, Output Current & Reference Current 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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