? about diodes - Page 1
Forum section: electronics / general

author: Dennis FK
author_rank: Newbie
timestamp: September 03, 2022, 01:21:26 pm
content: I'm starting to run out of 1N4007 diodes efter 30 years, so I bought some from china....The china diode are 2.3mm roundand the leads are only 0.45mm (compaired to my 30 years old witch is 3mm round and the legs are 0.8 )They seems very flimsy, but I have no idear if "original" diodes are that small?

author: Zeyneb
author_rank: Regular Contributor
timestamp: September 03, 2022, 01:30:40 pm
content: I don't know what officially should be it. But I recently bought from Digikey 1N4007GDICT-ND. I measured these right now. The body OD is 2.66mm and the leads are 0.81mm in diameter.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 03, 2022, 10:16:17 pm
content: DO-41 and other ancient JEDEC packages are quite loose in their dimensions. Though 0.45mm is out of spec.It might be actually a plastic version DO-35 or the like. Or just straight up cheaped out. I certainly wouldn't run them at full current. Mind, I'd also be suspicious enough to test them for voltage (if you apply a low current i.e. <1mA, they should avalanche stably, getting quite hot in the process but not failing outright -- if you don't have a 2kV+ DC supply, just turning up the (AC) voltage somewhat past what you need for a given application, and checking for reverse current or excess heating, should be good enough. They will most likely cook off shorted if you go too far, use a fuse and it's fine.TimP.S. Consider more descriptive titles in the future, like this one. A "?" about diodes could beanythingand no one has any way to guess until they click on it.

author: Dennis FK
author_rank: Newbie
timestamp: September 04, 2022, 10:58:06 am
content: Hi. Iøll do that in the future

author: gamalot
author_rank: Super Contributor
timestamp: September 04, 2022, 11:28:31 am
content: I have some cheap unknown brands 1N4007 from China, the OD of body is 2.4mm, which is OK. The leads are 0.5mm in diameter which is a lot thinner than what those big names say in their datasheets.That wouldn't be a big deal, I wouldn't put 1 amp through them - that would mean 1 watt of power dissipated and a 100-degree temperature rise!

author: Vovk_Z
author_rank: Super Contributor
timestamp: September 05, 2022, 08:06:44 pm
content: A thin lead diode type may be 1A7 or some other type in between.

author: golden_labels
author_rank: Super Contributor
timestamp: September 08, 2022, 11:08:37 am
content: Note that some diodes sold nowadays as DO-41 are really “like DO-41”, while the actual package is some version ofDO-204.I quickly made a summary ofminimumsizes from one reputable vendor (TME):Code:Manufacturer Length Dia-major Dia-minorDC Components 4.20 2.00 0.60Diotec 4.60 2.50 0.70CDIL 4.05 2.30 0.75Daco 4.10 2.00 0.71Vishay 4.10 2.00 0.71Luguang 4.20 2.00 0.71Micro Commercial 4.10 2.00 0.70Yangjie 4.22 2.03 0.69Onsemi 4.10 2.00 0.71Taiwan Semi 4.20 2.00 0.71Diodes Incorporated 4.06 2.00 0.71So the outer diameter seems ok. The wire diameter does not, clearly.

author: strawberry
author_rank: Super Contributor
timestamp: September 08, 2022, 05:58:11 pm
content: 0.01A and 1Ato approximate internal resistance (die size) between china and that other 1N400X diode*heating during measurement may affect precisionI bet that epoxy is not as heat resistant ( fire )same with resistors