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Projects => How Do I? Beginner's Paradise. => Topic started by: harryklippton on March 07, 2020, 05:43:14 PM

Title: Germanium diode help understanding anode, cathode, and markings
Post by: harryklippton on March 07, 2020, 05:43:14 PM
Hey y'all, I'm working on a retrograde build and have some more general diode questions. I have a bag of 1N34as from Tayda, and a much smaller quantity of "1N34a work-alikes" from small bear. (I think) I understand that the white stripe on a silicon diode indicates the anode, but when it comes to germaniums, they seem to be marked in many different ways. Here are my questions:

Are the 1N34as from Tayda really 1n34A?

What are the work-alikes from Small Bear actually?

Do the stripes on the germaniums also indicate the anode?

How can I test diodes? What information can I determine by testing myself?

Pics attached of the aforementioned diodes. Thanks!
Title: Re: Germanium diode help understanding anode, cathode, and markings
Post by: midwayfair on March 07, 2020, 05:52:24 PM
Your multimeter should have a setting that looks like the schematic symbol for a diode. You can measure the forward voltage (how much voltage is dropped across the diode, which might be different between two multimeters but you can get a consistent reading for your own usage) and determine which side is the anode for any particular diode. You can also measure the resistance across the diode, which can matter in very rare circumstances.

The ones from Tayda are constructed like and have the forward voltage of older 1N34A. They're fragile though and they are often prone to being out of spec or having runaway leakage. I haven't bought them recently, but I used to be lucky to get 5 good ones out of 10.

The ones from smallbear could be basically anything.

Part numbers are meaningless for the most part.
Title: Re: Germanium diode help understanding anode, cathode, and markings
Post by: harryklippton on March 07, 2020, 06:16:50 PM
Thank you midwayfair. So part number doesn't really matter as long as the forward voltage is on spec, right? Makes sense.
Title: Re: Germanium diode help understanding anode, cathode, and markings
Post by: harryklippton on March 07, 2020, 08:02:17 PM
Quote from: harryklippton on March 07, 2020, 05:43:14 PM
(I think) I understand that the white stripe on a silicon diode indicates the anode

Whoops got this backward but I'm good now