I saw an article somewhere but i cant find it now. I need to test if J201's I have are the real deal or fake. How do I go about this?
Thanks
I'm not sure if you are looking for this (https://viva-analog.com/jfet-characterization-technique-using-only-9v-battery-and-dmm/) but you can measure your transistors using described method. From my experience with J201 transistors - through hole and smd, real deal and fake. All the J201 in TO92 package I have are fake ones. I bought them from ebay, aliexpress, locally..
SMD is the opposite, no complains. If you have J201 in TO92 package and measure Vp - 1.6V, 1.8V - it's a fake one.
I've measured dozens of MMBFJ201 transistors (smd).. cannot remember a single one with Vp higher than 1.1V.
Usually it's somewhere between 0.65V and 0.9V.
T
Quote from: temol on August 18, 2020, 07:20:21 AM
I'm not sure if you are looking for this (https://viva-analog.com/jfet-characterization-technique-using-only-9v-battery-and-dmm/) but you can measure your transistors using described method. From my experience with J201 transistors - through hole and smd, real deal and fake. All the J201 in TO92 package I have are fake ones. I bought them from ebay, aliexpress, locally..
SMD is the opposite, no complains. If you have J201 in TO92 package and measure Vp - 1.6V, 1.8V - it's a fake one.
I've measured dozens of MMBFJ201 transistors (smd).. cannot remember a single one with Vp higher than 1.1V.
Usually it's somewhere between 0.65V and 0.9V.
T
I guess the DMM can measure Idss across the battery poles.
(https://i.postimg.cc/FY2Xyfyg/j-FETVp-Idss-768x560.jpg) (https://postimg.cc/FY2Xyfyg)
(http://www.lynx.net/~jc/BATTERY-FLAMES.png)
nothing like breaking the rule that says you can't short out a battery ...
A 100 to 220 ohm resistor in series with the battery is reasonable protection. 1k is better but then the onus is on you to check the measurements aren't wrong because of the 1k.
Quote from: Eb7+9 on August 18, 2020, 08:40:50 PM
(http://www.lynx.net/~jc/BATTERY-FLAMES.png)
nothing like breaking the rule that says you can't short out a battery ...
Well, thats how i read the page 😁
Current is measured through your meter, not across it. Break the connection and place your meter as if it were the wire that connects the positive battery terminal to the transistor.
Quote from: Steben on August 19, 2020, 01:38:56 AM...thats how i read the page 😁
A literal reading comes out like this:
(https://i.postimg.cc/GB6mvR8D/Steben-s-FETs-42.gif) (https://postimg.cc/GB6mvR8D)