I am attempting to lay out a schematic onto veroboard, this is my first time using F.E.T transistors and looking at the circuit, I don't know what pins are what....... I have the pin out for the 2N5951 but although the gate is clear to see, the other two connections look identical, I don't know which is the source and which is the drain according to the schematic I am following.

Neil.

 

I am attempting to lay out a schematic onto veroboard, this is my first time using F.E.T transistors and looking at the circuit, I don't know what pins are what....... I have the pin out for the 2N5951 but although the gate is clear to see, the other two connections look identical, I don't know which is the source and which is the drain according to the schematic I am following.

Neil.

Unless we are to guess, you'd better attach the schematic.

 

You are to guess ;-)

 

The it's the left one.

 

Are you sure?.....i don't want it to smoke

 

The pinout is given here.

 

Yes as I said...i already have the pin out, my issue is that on the schematic, the gate is the only pin that is Identifiable being the one with the arrow on it, the other pins either side look identical, one going to ground via a resistor and the other directly connected to the positive supply.

 

The one connected to the positive supply is the drain.
I'll leave you with the process of elimination.

 

Good job I asked, I assumed.that to be the source ....

Thanks for your help guys.

Neil.

 

Good job I asked, I assumed.that to be the source ....

Thanks for your help guys.

Neil.

Some JFETs are symmetrical and work with D/S either way round - but don't count on it without checking the data sheet.

Some manufacturers get confused about pin layouts on second sourced parts - I don't know any easy way to tell for sure with a JFET. It may work better one way round than the other. Usually the gate is in the wrong position - that's a little easier to figure out.

Some parts have a suffix letter - sometimes that suffix indicates an alternative pin layout.