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Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
these are very slow, low-HFE transistors (HOT - horizontal output transistor). Usable for high voltage switching applications to few tens of kHz maximum...
Registered Member #1408
Joined: Fri Mar 21 2008, 03:49PM
Location: Oracle, AZ
Posts: 679
I did the same thing some time back. Here is the spec sheet. . The emitter (to base) shows 6v while everything else is high. Horizontal output transistors don't appear to function as switching transistors in the majority of flyback drivers. I have actually tried a few as I thought that the first one was blown as it did zip. The switching transistor I always hunt for is that MJE13009, as it preforms very well in quite a few flyback drivers. ]c5148_-nte_equiv.pdf[/file]
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
Grenadier wrote ...
Hmm... I'll hook one up to one of my superflybacks like a 2n3055 and see what happens.
edit; well I just looked at one, the c5148 and it supposedly has a speed of .15uS. Doesn't seem too slow.
with an hFe of less than 10 youll need bukoo current to get that thing to switch. Hfe = 8 then ... Ib X Hfe = Ic ... so lets say you want 3 amps of Ic to your primary. then, 375mA x 8 = 3A out. so you will need to supply 0.375 amps to the base to get 3 amps out, also look at quicksilver's pdf post, the base to collector Vmax is 1500, the collector to emitter is 800V max, so you cant switch more then 800V minus your safety margin. its really a 800v transistor then.
your 2N3055 will take a base current of 50mA to do the same. thats a big difference.
Registered Member #1408
Joined: Fri Mar 21 2008, 03:49PM
Location: Oracle, AZ
Posts: 679
Patrick: That was a pretty darn useful explanation. I believe it was also in Circuit Designer's companion in "active components". I wonder about my reading retention every once and a while....
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HV transistors
