13 basic transistor application

University of Bahrain

Electronic Circuits I ITCE263

Dr. Mohammed Majid Al Khalidy

Lesson 13

Basic Transistor Application

Dr. Mohammed Majid al Khalidy


The transistor in the circuit is switched between cutoff and saturation.

An npn bipolar inverter circuit used as a switch

If vI < VBE (on), then iB = iC = 0 and the transistor is cut off. If the load were a motor, the motor would be off with zero current.

If vI = VCC and if the ratio of RB to RC , where RC is the effective resistance of the load, is less than β, then the transistor is usually driven into saturation.


which means that:

In this case, a collector current is induced that would turn on the motor or the LED, depending on the type of load.


Calculate the appropriate resistance values and transistor power dissipation for the two inverter switching configurations shown in the Figure below.

Example

below

Solution:


below



Determine the currents and voltages in the circuit shown in Figure below.

Example

Solution:


The bipolar inverter circuit can also be used to amplify a time-varying signal


Example



References: 1] Microelectronic circuits by Sedra /Smith, 6th edition. 2] Microelectronics Circuit Analysis and Design (4th Edition) by Donald Neamen. 3] Electronic Devices by, Floyd.


Engineering

13 basic transistor application