What is the difference thyristor, diode, and a resistor ?

Question

Does a diode and a resistor combined make a thyristor ? or is it a combination of a diode and a transistor ?

Answer 1

No. A diode is a semiconductor device that allows the flow of current in one direction only. Think of it like a check valve in plumbing - the water can flow through in one direction, but the valve shuts off when the water tries to flow backwards. A thyristor is a switch that, when in the "on" state, allows the flow of current in either direction, and in neither direction when "off" -- like a water tap. A resistor is a different device, which limits the flow of current - like opening or closing the tap.

That's the "simple" explanation!

Answer 2

A diode only conducts current when it is forward biased. This means current only flows through it in one direction.

A resistor conducts current in both directions, but with some amount of intentional loss (resistance).

A thyristor is a switch like a transistor that has the unique characteristic that once it is triggered on, it will stay switched on as long as it is forward biased.

SCRs are a type of thyristor that are composed of a pair of transistors that are arranged in such a way that when the trigger pulse comes, one transistor latches the other one on as long as the device is forward biased. When it is reversed biased, the device turns off. SCRs only conduct one way, like diodes.

Triacs are thyristors that conduct both ways, and only turn off when the current through them reaches 0. They can be built by putting two SCRs in inverse parallel and connecting the gates together.

So to answer your second question, neither a diode and resistor, nor a diode and transistor make up a thyristor. Two transistors can make a thyristor.

Answer 3

a thyristor is like 2 diode stuck together. there is a third line that comes in the center called the gate. once a certain voltage is applied to the gate the thyristor allows current to flow in the opposite direction as a normal diode would not allow. see below for wikipedia description of how the gate affects the circuit.