Why do u call a transistor a current controlled device ?

Answer 1

I don't, I just call em chips.

Answer 2

Before knowing about the transistor, we shall first know the difference between a transformer and transistor.

An ideal transformer separates two circuits; one connected to its primary coil and another connected to its secondary coil.

The input power equals the out put power. The input voltage is either smaller or greater than the output voltage depending upon the number of turns in the primary and secondary coils of the transformer.

But transistor like devices is not used to transform the power from one circuit to another circuit.

However, we are having two circuits one connected to the input and another connected to the out put. There is separate power in the out put and another power in the input.

By varying the current or voltage in the input we control the current or voltage in the output.

If we vary the voltage in the input circuit and if the out put voltage correspondingly varies, the device is called voltage controlled devices. The vacuum tube valves used formerly in amplifier are voltage controlled device.

If we vary the current in the input circuit and if the out put current correspondingly varies, the device is called current controlled devices. Transistors are current controlled devices.

In transistors, the current is controlled by input resistance and out put resistance of the device.

The variation in the input resistance is reflected upon the out put resistance. That is why the name transistor-(tran - resistor).

The resistors change such a way that the collector current is always nearly equal to the emitter current, thereby making the device suitable for controlling the current

Answer 3

It is a current controlled device because for a particular Base to Emitter Current the Collector to Emitter Current is relatively constant regardless of the Collector to Emitter Voltage. Transistor Curves done on a curve tracer show this characteristic.

Answer 4

Be careful!...There are transistors and there are transistors! What you are referring to is a "Bipolar Junction Transistor", or BJT where the currrent flowing from the collector to the emitter is determined by the CURRENT flowing into or out of the Base terminal.

For a "Field Effect Transistor" or FET, the current flowing through the transistor is determined by the VOLTAGE on the Gate terminal.

Answer 5

Simply because a small amount of current flow through the base-emitter junction controls the much larger current flow through the collector-emitter junction.

Note: There are several types of transistors and I assume you are talking about the more familiar and common type.
For more information on the different types and how they are controlled, do a search on "transistor."

Answer 6

the two the BJT and the FET have 3 connections. The BJT has Collector, Base and Emitter. There are 2 types, the NPN or the PNP transistor. Taking working example the NPN variety; if one applies a voltage to the Collector, valuable with recognize to the Emitter, a modern-day will bypass from the Emitter to the Collector. If now a small voltage, valuable with recognize to the Emitter is utilized to the backside, a small modern-day will bypass from the Emitter to the backside, however the present from Emitter to Collector will strengthen by potential of a huge quantity. by potential of changing the Emitter-to-Base modern-day by potential of very small quantities, super modern-day variations will ensue betwen Emitter and Collector. FET's even have 3 connections, Drain, Gate and source. There are 2 situation-loose types P-channel and N-channel. Taking the N-channel variety for evaluation, the voltages utilized could be reminiscent of the NPN transistor. Collector = Drain, Base = Gate and Emitter = source. Now a favorable voltage with recognize to the source utilized to the Drain will effect in a modern-day from the source to the Drain. If a small voltage valuable with recognize to the source is utilized to the Gate the source-to-Drain modern-day will strengthen very much resembling the NPN transistor. the massive difference right this is, that very nearly no modern-day flows from the source to the Gate. the electrical powered container on my own has the outcomes of controlling the present interior the path of the gadget, for this reason container-result-Transistor. whilst you're acquainted with the previous valve radio contraptions, --- the N-variety FET applications resembling a Triode.

Answer 7

Very simpled, but because they can affect the flow of the current.