Contents
What is output resistance of BJT?
Since a high input resistance is desirable for a voltage amplifier, we often use a base resistor on a BJT to improve the input resistance at the cost of gain. The output resistance of the common-emitter amplifier is just Rout = RC.
What is the output resistance of CE transistor?
It offers high current gain (typically 200), medium input resistance and a high output resistance. The output of a common emitter amplifier is 180 degrees out of phase to the input signal.
What determines the output resistance of a common emitter amplifier?
The input and output impedance of an amplifier is the ratio of voltage to current flowing in or out of these terminals. The input impedance may depend upon the source supply feeding the amplifier while the output impedance may also vary according to the load impedance, RL across the output terminals.
What is dynamic output resistance?
Dynamic output resistance is defined as the ratio of change in output voltage or collector voltage (VCE) to the corresponding change in output current or collector current (IC), with the input current or base current (IB) kept at constant.
Which is the common emitter configuration of BJT?
Common emitter configuration of BJT The common emitter circuit is probably the most widely used transistor configuration. The emitter electrode is common to both input and output circuits. The common emitter amplifier has a typical input impedance of 1kilo ohms and a typical output impedance of 10 kilo-ohms.
What is the output resistance of a common emitter?
Here for common emitter configuration output current is Ic and output voltage is Vcb. So, for common emitter connection, output resistance ( Ro) = change in Vce / change in Ic. As we see above in points of output characteristics, the output resistance of a circuit is high. In this connection, output resistance is in a range between 50 KΩ.
Why are the resistors of a BJT amplifier different?
The two resistors have totally different functions. RC is totally fundamental to the operation of a common-emitter amplifier. It determines the voltage gain of the amplifier. If you removed it, you simply wouldn’t have a working circuit, because there’d be no path for current to flow through the collector of the BJT.
What does output resistance mean in a transistor?
Output resistance is generally the ratio of output voltage to output current. Here for common emitter configuration output current is Ic and output voltage is Vcb. So, for common emitter connection, output resistance ( Ro) = change in Vce / change in Ic.