4 Pin SCR

[fsahmed]

Can anyone please tell me about 4 pin SCRs, their construction, working, application .


Thanks in advance.

 

[Hero999]

I'ver never seen opne before.

Is this a part in a circuit?

Look at the part number and Google the datasheet.

 

[Nigel Goodwin]

They are usually called a PUT (Programmable Unijunction Transistor), it's a PNPN construction, with all four layers connected to wires - an SCR has one of the middle layers not connected.

You can easily make one with an NPN and a PNP transistor.

 

[fsahmed]

Thanx Nigel, for telling me it is just a PUT...... I had only heard of a 4 pin SCR in a conversation and became desperate to know what it is. Thanx

 

[Roff]

Huge SCRs have a fourth terminal which is the cathode potential lead or terminal. This is necessary as a reference for the gate drive.