What is the difference between a transistor and a variable resistor?

What is the difference between a transistor and a variable resistor?

A resistor is considered a passive device and has two connections and a nominal fixed resistor.

A transistor is considered an active device and has three connections.

A terminal is a control terminal, and when this terminal is controlled accordingly, it affects the apparent resistance between the other two. Hence the term “semiconductor”.

As a result, the resistance is subject to a fixed restriction on the current flow in the device, the amount depending on the fixed resistance value R.

The current that flows is = V / R.

In the transistor, the amount of restriction (by the base current of a BJT or the gate voltage of a MOSFET) can be modulated using the third terminal and therefore becomes an active control device. You can switch, amplify or modulate at high speed.

In Short,

A resistor has a fixed resistance that does not change. It also has only two connections, an input and an output, the output depending on the input and the resistance.

A transistor is like a resistor, except that its resistance can be controlled by a second input called the base input.

In addition, the gate input of the transistor is the emitter and the output is the collector (for some reason also backwards).

When a negative current is applied to the base input, the resistance increases, which prevents current from flowing from the emitter to the collector and a transistor acting as a switch.

If a positive current is supplied to the base and a second negative current source is connected to the emitter, the input is amplified in proportion to the base current

Google serves cookies to analyze traffic to this site and for serving personalized ads. Learn more