# Electronic Devices and Circuits Questions and Answers – Conversion Formulas for the Parameters of the Three-Transistor Configurations

This set of Electronic Devices and Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Conversion Formulas for the Parameters of the Three-Transistor Configurations”.

1. What are the units of hybrid parameter hie for a transistor?
a) Ohms
b) Siemens
c) Voltage
d) Dimensionless

Explanation: The hybrid parameter hie is the input impedance in a common emitter circuit. Hence, the units of this hybrid parameter will be measured in Ohms. It is the same unit as the hybrid parameters hib and hic.

2. How many hybrid parameters are there in a transistor circuit?
a) 16
b) 8
c) 12
d) 4

Explanation: There are a total of 12 hybrid parameters in a transistor circuit. There are four parameters for each mode of operation. Each mode of operation has only four working hybrid parameters, which are derived from the four basic hybrid parameters: h11, h12, h21 and h22. The 12 transistor parameters are: hib, hie, hic, hrb, hre, hrc, hfb, hfe, hfc, hob, hoe and hoc.

3. What is the equivalent hybrid parameter for the transistor hybrid parameter hre?
a) h11
b) h12
c) h21
d) h22

Explanation: The transistor hybrid parameter hre is equivalent to the hybrid parameter h12. The transistor hybrid parameter is a measure of the open circuit reverse voltage transfer ratio. The transistor equivalent parameter is a ratio of the voltages across two terminals.

4. What is the equivalent hybrid parameter for the transistor hybrid parameter hfe?
a) h11
b) h12
c) h21
d) h22

Explanation: The transistor hybrid parameter hfe is equivalent to the hybrid parameter h21. The transistor hybrid parameter is a measure of the output short circuit forward current gain. The transistor equivalent parameter is a ratio of the currents across two terminals.

5. What is the equivalent hybrid parameter for the transistor hybrid parameter hoe?
a) h11
b) h12
c) h21
d) h22

Explanation: The transistor hybrid parameter hoe is equivalent to the hybrid parameter h22. The transistor hybrid parameter is a measure of the input open circuit with output admittance. The transistor equivalent parameter is a ratio of the current across one terminal and the voltage.

6. What is the equivalent hybrid parameter for the transistor hybrid parameter hib?
a) h11
b) h12
c) h21
d) h22

Explanation: The transistor hybrid parameter hib is equivalent to the hybrid parameter h11. The transistor hybrid parameter is a measure of the output short circuit with input impedance. The transistor equivalent parameter is a ratio of the voltage across one terminal and the current.

7. Which external parameters affect the transistor hybrid parameters?
a) Temperature
b) Collector current
c) Temperature and collector current
d) External parameters don’t affect hybrid parameters

Explanation: The transistor hybrid boundaries are not consistent and change with temperature, collector current and collector emitter voltage. Consequently, while planning the circuit the hybrid boundaries ought to be estimated under similar conditions as the actual circuit.

8. Why do we use hybrid parameter models while describing the working of a transistor?
a) Ease of use
b) Characterize bipolar transistors
c) Acts as a switch
d) Makes no difference

Explanation: H-boundaries are one framework for describing bipolar semiconductors. The h-boundaries of a semiconductor will give you a smart thought what it can do, how to utilize it viably in a circuit, and whether it is proper for a specific circuit. Hence, we use them to characterize bipolar transistors.

Sanfoundry Global Education & Learning Series – Electronic Devices and Circuits.