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If I’m understanding the component guide when looking at the flat side of the silkscreen for a bipolar transistor orientation is c b e, however I don’t see orientation for a fet. If I am grasping the functionality source would be equivalent to base but I can’t find positioning of gate and drain. As I understand it they are considered to be reversible but I assume there is a correct orientation given that they have different names. Thanks
Always follow the silkscreen orientation if using the transistors specified in the build document
Not all BJTs or FETs have the same pinout corresponding to flat side orientation, some could be CBE or EBC left to right some even have strange pinouts with C in the centre the same applies to FETs it could be DGS, SGD or GSD etc
Unfortunately there is no standard pinout between manufacturers you should always go by the datasheet or Google for transistor pinout e.g. 2Nxxx pinout
You can also buy cheap transistor testers or a Peak Atlas DCA55 or 75 that will tell you a transistors pinout and other information
Got all that. From left to right looking at the flat side of the silk screen what orientation do I need to place the pins in for a jfet? That is once I have verified the pin out of the transistor itself. In the component guide there is a picture which shows the e b c orientation but no indication that I saw referring to g s d, s d g etc. That doesn’t mean it’s not there I may have missed something. I don’t guess it matters but I’m referring to the 4 j201 s in the sunn t. If I’m unable to find the data sheet once I have the parts in hand I believe I can Devine the order using a multimeter. I promise I tried to research this thoroughly and answer the question myself before posting.
I’m not sure I understand what you’re asking Ollie
You’d just place your J201s as per the silkscreen flat side to flat side
The silkscreen is correct for a J201
So regardless of the brand the pin out on the j201 will be the same? I believe that looks to be d s g. If you remember last week I had my Bc549c s in backwards in the green Russian so I guess I was being overly cautious in regards to the seemingly random pin out configurations on these devices from brand to brand. I am now socketing all transistors so even if I mix it up I won’t have to break out the solder sucker. Sorry for the confusion and thank you for the help.
Ollie – as Billy points out, BJTs and FETs and even JFETs do not have the same pin identifiers. BJT pinouts are typically all over the map – there is no “standard” pinout ordering. Same pretty much goes for FETs.
What a lot of builders don’t know about JFETs is that the Drain and Source are interchangeable. JFETs are symmetrical devices. Simple FETs are not and all three legs need to be properly identified as per their respective datasheets. (BJTs certainly are not.) For JFETs, identifying the Gate is vital. The other two legs can go where they most readily fit. And it’s OK to cross legs (if need be) when substituting parts – just be sure to use a bit of insulation on the crossed legs so they do not short together.
99.99% of any BJT, FET or JFET of the same part ID (J201, BC549, or what have you) will have the the same pinout as other parts of that same type – even across manufacturers.
Using sockets is always a good idea during initial builds to easily swap or re-orient a part if need be.
And as Billy points out for your J201 JFETs, just match the shape of the silkscreen to the shape of the J201 – if that build calls for J201 JFETs.
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