First Collector Current Of BJT Differential Amplifier Calculator

Formula Used:

\[ i_{C1} = \frac{\alpha \cdot i}{1 + e^{\frac{-V_{id}}{V_{th}}}} \]

Common Base Current Gain (α):

Current (i):

Differential Input Voltage (Vid):

Threshold Voltage (Vth):

First Collector Current (iC1):

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1. What is the First Collector Current of BJT Differential Amplifier?

The First Collector Current in a BJT Differential Amplifier represents the current flowing through the collector of the first transistor in the differential pair configuration. This current is crucial for understanding the amplifier's operation and performance characteristics.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ i_{C1} = \frac{\alpha \cdot i}{1 + e^{\frac{-V_{id}}{V_{th}}}} \]

Where:

\( \alpha \) — Common Base Current Gain
\( i \) — Total current
\( V_{id} \) — Differential Input Voltage
\( V_{th} \) — Threshold Voltage
\( e \) — Napier's constant (approximately 2.71828)

Explanation: This formula describes how the collector current in the first transistor varies with the differential input voltage in a BJT differential amplifier configuration.

3. Importance of First Collector Current Calculation

Details: Accurate calculation of the first collector current is essential for designing and analyzing differential amplifiers, determining gain characteristics, and ensuring proper circuit operation in various electronic applications.

4. Using the Calculator

Tips: Enter the common base current gain, total current, differential input voltage, and threshold voltage. All values must be valid (α > 0, i > 0, Vth > 0).

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range for common base current gain?
A: Common base current gain (α) typically ranges from 0.95 to 0.995 for most bipolar junction transistors.

Q2: How does differential input voltage affect the collector current?
A: The collector current varies exponentially with the differential input voltage, following the characteristic transfer function of the differential pair.

Q3: What is the significance of threshold voltage in this context?
A: The threshold voltage determines the sensitivity of the current division between the two transistors in the differential pair.

Q4: Can this calculator be used for MOSFET differential amplifiers?
A: No, this specific formula applies to BJT differential amplifiers. MOSFET differential amplifiers have different characteristic equations.

Q5: What are practical applications of BJT differential amplifiers?
A: BJT differential amplifiers are widely used in operational amplifiers, instrumentation amplifiers, and various analog signal processing circuits where differential signaling is required.