#garfield | Logs for 2016-09-15

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[22:58:11] <katsmeow> "boss tell me to clip all tabs off the to-220 in stock, so i cut all 3 tabs off each one, all 3000 transistoes in stock, before lunch!"
[23:29:16] <rue_house> heya
[23:29:38] <rue_house> hehe
[23:30:05] <rue_house> how do you cut the tab off a transistor without disturbing the die?
[23:31:19] <katsmeow> saw?
[23:31:51] <katsmeow> afaik, all the leads and tabs are sheared irl
[23:40:32] <rue_house> but if you deform the back, it'll tear the bond wires off the die?
[23:42:55] <katsmeow> prolly
[23:45:52] <rue_house> this week I tried to grind back the tab of a 7805
[23:46:00] <rue_house> afterwords it output 2.8V
[23:46:43] <katsmeow> scientists found two chromosome base pairs, that if switched, causes the human body to grow up *looking* male or female, unrelated to the XY chromosomes
[23:47:21] <katsmeow> what did you grind with?
[23:47:38] <rue_house> bench
[23:47:52] * katsmeow would clamp it to a plate and use an fine abrasive disk in a dremel
[23:47:57] <rue_house> it might have overheated (3 or 5 times)
[23:48:08] <katsmeow> yea,, gringing makes thengs bloody hot
[23:51:08] <rue_house> so I been building a motor driver
[23:51:13] <rue_house> for a vac motor at 48VDC
[23:51:17] <rue_house> I finished today
[23:51:33] <rue_house> but the flyback diode blew, seems it was only rated for 40V
[23:51:50] <rue_house> so I upgraded it, and the fet is getting really hot
[23:52:12] <rue_house> its drive voltage is fine, so its suffereing from a lower flyback votlage then the flyback diode has
[23:52:35] <rue_house> I tommorow I'll upgrade it to the 60A 600V IGBT
[23:52:36] <katsmeow> huh?
[23:53:17] <katsmeow> is the fet turning on and off fast enough? is the gate drive power heating the fet?
[23:53:40] <rue_house> yea, its just 600Hz, and the switcing is find
[23:54:01] <rue_house> I'v learned that most of the time the reverse flyback is what causes them to get hot
[23:54:16] <katsmeow> so the body diode is conducting?
[23:54:26] <rue_house> yup
[23:58:39] <rue_house> http://www.thingiverse.com/thing:30571
[23:58:47] <rue_house> I have the "high price model" he shows