![]() ![]() When the input voltage (output voltage from the op-amp) is negative (with respect to the common node), the PNP transistor conducts. Current flows from the positive power supply to the common node through the motor, and the motor turns in one direction. When the input voltage (output voltage from the op-amp) is positive (with respect to the common node), the NPN transistor conducts. The class B amplifier uses one NPN and one PNP transistor. The class B amplifier drives the DC motor. The output of the op-amp drives a class B amplifier. The potentiometer output is buffered using an op-amp. Ī user sets the position of the potentiometer to produce a voltage that represents a required motor speed.The circuit is operated from a dual-rail power supply where +V S is positive power supply voltage and –V S is negative power supply voltage. If the circuit attempts to switch the transistor ON and OFF too fast, the transistor cannot react fast enough and the result will be incorrect circuit operation.įigure 8.43. When used as a switch (particularly applicable for motor control), the switching ON and OFF times also must be considered to ensure correct operation of the circuit in which the transistor is used. įor the power transistor, the safe operating region (SOAR) specifies the safe limits of operation for the transistor in terms of the operating voltages and currents for continuous operation (continuous current and voltage levels) as well as for levels that exceed the continuous operation region for a limited time period.Īudio amplifiers (the output stage of the amplifier driving the speakers).Example applications for power transistors include: ![]() Both BJTs and MOSFETs can be used to produce either amplifier or analogue filter circuits (linear applications) or switching applications (nonlinear applications). ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |