transistor is a current-controlled device. current amplification only in common basic mode, only voltage amplification occurs, in common collector mode, only current amplification occurs, in common emitter mode, amplification of voltage and current occurs.
Does a transistor amplify current or voltage?
A transistor is a device that regulates the current or voltage and serves as a switch or gate for electronic signals. The transistors consist of three layers of a semiconductor material, each capable of supporting a current. A small variation in the current or voltage at the inner semiconductor layer (which serves as a control electrode) produces a large and rapid change in the current flowing through the entire layer. component. the component can thus act as a switch, opening and closing an electronic gate several times per second.
Transistors are designed to meet the requirements of the application and this is done by changing the parameters of a particular category of transistors. the alphabet found written on it also indicates the category of this transistor. However, there are on the market of transistors capable of amplifying the current as well as the voltage or the power according to their capacity of treatment of the current. High power amps are transistors capable of withstanding high current.
transistor is a controlled current device. it therefore amplifies the current and not the voltage. but it is also impossible to introduce current into a transistor without voltage. therefore, we correctly polarize the transistor so that we can supply an input current for amplification.
Similarly, the output current is also taken at the collector terminal and the amplification can be observed at this point.
this gain or amplification factor of a transistor is given by ?. it has a value between 20 and 200 for most general purpose transistors.
a transistor can amplify the current and it can amplify the voltage and it can do both at the same time.
It does not actually amplify the current entering the transistor, but it examines the current entering the base cable and allows a higher current to be transmitted from the power rail and via the collector-emitter cables. the transistor is said in emitter-follower mode for this to happen. (and other modes too)
a transistor can also amplify the voltage is seen on the base.
this is done in transmitter common mode where the transmitter is connected to the 0v rail and the collector has a load resistor.
- when the voltage on the base is very close to 0.6v, the transistor is just at the point where it is lit and the voltage on the collector will be 8v for a 9v supply.
- If the voltage on the base increases by 50 mV, the transistor will turn on more and the voltage on the collector will drop to say 3 v.
- we call this voltage boost, because 50mv has produced a change of 5000mv and it’s a 100: 1 gain or a 100x amplification (100x)
at the same time, we did not may need only a current of 0.1 mA to deliver 50 mv climb into the base of the transistor and the collector may be able to provide 1mA and 3v to an external load. this is a current gain 10 times the 100x voltage gain.
