## Collector-Base Capacitance Solution

STEP 0: Pre-Calculation Summary
Formula Used
Collector Base Capacitance = Emitter Base Junction Area*sqrt((Charge*Permittivity*Doping Density)/(2*(Built In Potential+Reverse Bias Junction)))
Ccb = A*sqrt((q*ε*Nb)/(2*(ψo+Vrb)))
This formula uses 1 Functions, 7 Variables
Functions Used
sqrt - Square root function, sqrt(Number)
Variables Used
Collector Base Capacitance - (Measured in Farad) - Collector Base Capacitance is simply the capacitance of the collector-base junction including both the flat bottom portion of the junction and the sidewalls.
Emitter Base Junction Area - (Measured in Square Meter) - Emitter Base Junction Area is a P-N junction formed between the heavily doped P-type material (emitter) and the lightly doped N-type material (base) of the transistor.
Charge - (Measured in Coulomb) - Charge a characteristic of a unit of matter that expresses the extent to which it has more or fewer electrons than protons.
Permittivity - (Measured in Farad per Meter) - Permittivity is a physical property that describes how much resistance a material offers to the formation of an electric field within it.
Doping Density - (Measured in Electrons per Cubic Meter) - Doping Density is a process in which certain impurity atoms, such as phosphorus or boron, are introduced into the semiconductor to alter its electrical properties.
Built In Potential - (Measured in Volt) - The Built In Potential affects the size of the depletion region, which in turn influences the capacitance of the junction.
Reverse Bias Junction - (Measured in Ampere) - Reverse Bias Junction refers to the condition in a semiconductor device, where the voltage applied across the junction opposes the normal flow of current through the device.
STEP 1: Convert Input(s) to Base Unit
Emitter Base Junction Area: 1.75 Square Centimeter --> 0.000175 Square Meter (Check conversion here)
Charge: 5 Millicoulomb --> 0.005 Coulomb (Check conversion here)
Permittivity: 71 Farad per Meter --> 71 Farad per Meter No Conversion Required
Doping Density: 26 Electrons per Cubic Meter --> 26 Electrons per Cubic Meter No Conversion Required
Built In Potential: 4.8 Volt --> 4.8 Volt No Conversion Required
Reverse Bias Junction: 2.55 Milliampere --> 0.00255 Ampere (Check conversion here)
STEP 2: Evaluate Formula
Substituting Input Values in Formula
Ccb = A*sqrt((q*ε*Nb)/(2*(ψo+Vrb))) --> 0.000175*sqrt((0.005*71*26)/(2*(4.8+0.00255)))
Evaluating ... ...
Ccb = 0.000171548906401606
STEP 3: Convert Result to Output's Unit
171.548906401606 171.5489 Microfarad <-- Collector Base Capacitance
(Calculation completed in 00.004 seconds)
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## Credits

Created by Rahul Gupta
Chandigarh University (CU), Mohali, Punjab
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Chandigarh University (CU), Punjab
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## < 13 Bipolar IC Fabrication Calculators

Resistance of Rectangular Parallelepiped
Resistance = ((Resistivity*Thickness of Layer)/(Width of Diffused Layer*Length of Diffused Layer))*(ln(Width of Bottom Rectangle/Length of Bottom Rectangle)/(Width of Bottom Rectangle-Length of Bottom Rectangle))
Impurity Atoms Per Unit Area
Total Impurity = Effective Diffusion*(Emitter Base Junction Area*((Charge*Intrinsic Concentration^2)/Collector Current)*exp(Voltage Base Emitter/Thermal Voltage))
Conductivity of N-Type
Ohmic Conductivity = Charge*(Electron Doping Silicon Mobility*Equilibrium Concentration of N-Type+Hole Doping Silicon Mobility*(Intrinsic Concentration^2/Equilibrium Concentration of N-Type))
Conductivity of P-Type
Ohmic Conductivity = Charge*(Electron Doping Silicon Mobility*(Intrinsic Concentration^2/Equilibrium Concentration of P-Type)+Hole Doping Silicon Mobility*Equilibrium Concentration of P-Type)
Collector-Base Capacitance
Collector Base Capacitance = Emitter Base Junction Area*sqrt((Charge*Permittivity*Doping Density)/(2*(Built In Potential+Reverse Bias Junction)))
Ohmic Conductivity of Impurity
Ohmic Conductivity = Charge*(Electron Doping Silicon Mobility*Electron Concentration+Hole Doping Silicon Mobility*Hole Concentration)
Collector-Current of PNP Transistor
Collector Current = (Charge*Emitter Base Junction Area*Equilibrium Concentration of N-Type*Diffusion Constant For PNP)/Base Width
Saturation Current in Transistor
Saturation Current = (Charge*Emitter Base Junction Area*Effective Diffusion*Intrinsic Concentration^2)/Total Impurity
Sheet Resistance of Layer
Sheet Resistance = 1/(Charge*Electron Doping Silicon Mobility*Equilibrium Concentration of N-Type*Thickness of Layer)
Resistance of Diffused Layer
Resistance = (1/Ohmic Conductivity)*(Length of Diffused Layer/(Width of Diffused Layer*Thickness of Layer))
Current Density Hole
Hole Current Density = Charge*Diffusion Constant For PNP*(Hole Equilibrium Concentration/Base Width)
Impurity with Intrinsic Concentration
Intrinsic Concentration = sqrt((Electron Concentration*Hole Concentration)/Temperature Impurity)
Transit Time of PNP Transistor
Transit Time = Base Width^2/(2*Diffusion Constant For PNP)

## Collector-Base Capacitance Formula

Collector Base Capacitance = Emitter Base Junction Area*sqrt((Charge*Permittivity*Doping Density)/(2*(Built In Potential+Reverse Bias Junction)))
Ccb = A*sqrt((q*ε*Nb)/(2*(ψo+Vrb)))

## How Does Collector-Base Capacitance Affect Transistor Performance?

The capacitance between the collector and base has implications for the transistor's high-frequency performance. It can slow down the transistor's response time at higher frequencies because it acts as a coupling or energy storage element. Manufacturers and circuit designers must consider this capacitance when operating BJTs in high-frequency circuits to ensure proper performance.

## How to Calculate Collector-Base Capacitance?

Collector-Base Capacitance calculator uses Collector Base Capacitance = Emitter Base Junction Area*sqrt((Charge*Permittivity*Doping Density)/(2*(Built In Potential+Reverse Bias Junction))) to calculate the Collector Base Capacitance, The Collector-Base Capacitance formula is defined in a bipolar junction transistor (BJT) refers to the capacitance between the collector and the base terminals of the transistor. This capacitance arises due to the depletion region and the charge storage within the transistor. Collector Base Capacitance is denoted by Ccb symbol.

How to calculate Collector-Base Capacitance using this online calculator? To use this online calculator for Collector-Base Capacitance, enter Emitter Base Junction Area (A), Charge (q), Permittivity (ε), Doping Density (Nb), Built In Potential o) & Reverse Bias Junction (Vrb) and hit the calculate button. Here is how the Collector-Base Capacitance calculation can be explained with given input values -> 1.7E+8 = 0.000175*sqrt((0.005*71*26)/(2*(4.8+0.00255))).

### FAQ

What is Collector-Base Capacitance?
The Collector-Base Capacitance formula is defined in a bipolar junction transistor (BJT) refers to the capacitance between the collector and the base terminals of the transistor. This capacitance arises due to the depletion region and the charge storage within the transistor and is represented as Ccb = A*sqrt((q*ε*Nb)/(2*(ψo+Vrb))) or Collector Base Capacitance = Emitter Base Junction Area*sqrt((Charge*Permittivity*Doping Density)/(2*(Built In Potential+Reverse Bias Junction))). Emitter Base Junction Area is a P-N junction formed between the heavily doped P-type material (emitter) and the lightly doped N-type material (base) of the transistor, Charge a characteristic of a unit of matter that expresses the extent to which it has more or fewer electrons than protons, Permittivity is a physical property that describes how much resistance a material offers to the formation of an electric field within it, Doping Density is a process in which certain impurity atoms, such as phosphorus or boron, are introduced into the semiconductor to alter its electrical properties, The Built In Potential affects the size of the depletion region, which in turn influences the capacitance of the junction & Reverse Bias Junction refers to the condition in a semiconductor device, where the voltage applied across the junction opposes the normal flow of current through the device.
How to calculate Collector-Base Capacitance?
The Collector-Base Capacitance formula is defined in a bipolar junction transistor (BJT) refers to the capacitance between the collector and the base terminals of the transistor. This capacitance arises due to the depletion region and the charge storage within the transistor is calculated using Collector Base Capacitance = Emitter Base Junction Area*sqrt((Charge*Permittivity*Doping Density)/(2*(Built In Potential+Reverse Bias Junction))). To calculate Collector-Base Capacitance, you need Emitter Base Junction Area (A), Charge (q), Permittivity (ε), Doping Density (Nb), Built In Potential o) & Reverse Bias Junction (Vrb). With our tool, you need to enter the respective value for Emitter Base Junction Area, Charge, Permittivity, Doping Density, Built In Potential & Reverse Bias Junction and hit the calculate button. You can also select the units (if any) for Input(s) and the Output as well. Let Others Know