I think I might have found my favourite ebay seller.
this link
Wow, 100pcs irfbc40 n-channel 600v 6.2amp 125W for $15 + shipping. I can get myself a lot of parts for the next burning festival
Hm... I wonder if they're genuine or fake, at that price.
Disclaimer: I am in no way related to that seller, but I may become addicted to his prices
this link
Wow, 100pcs irfbc40 n-channel 600v 6.2amp 125W for $15 + shipping. I can get myself a lot of parts for the next burning festival
Hm... I wonder if they're genuine or fake, at that price.
Disclaimer: I am in no way related to that seller, but I may become addicted to his prices
massimo said:
Yes T0-92s from Siemens. Exactly good for the business.
ikoflexer said:
Here http://search.datasheetcatalog.net/key/MTW20N50EI just happened to have four pieces of those on hand, but two are fried already while experimenting.
STW20NM60 can be used too. I've tried simulating a number of high voltage high power n-channel mosfets and they worked. Lots to choose from.
By the way, when you see old computers (or old CRT monitors) thrown in the garbage, or at your local university swap shop, guess what's in them? Usually high voltage mosfets
The easiest I can deploy are IRF820s and 840s. I would put a 250mW 12V (quitest Zener) right on the source & gate pins though. 820s have low Crss and I have them for antiblock grid drive buffers.
ikoflexer said:I think I might have found my favourite ebay seller.
this link
Wow, 100pcs irfbc40 n-channel 600v 6.2amp 125W for $15 + shipping. I can get myself a lot of parts for the next burning festival
Hm... I wonder if they're genuine or fake, at that price.
Disclaimer: I am in no way related to that seller, but I may become addicted to his prices
Watch for fakes.
ikoflexer said:I think I might have found my favourite ebay seller.
this link
Wow, 100pcs irfbc40 n-channel 600v 6.2amp 125W for $15 + shipping. I can get myself a lot of parts for the next burning festival
Hm... I wonder if they're genuine or fake, at that price.
Disclaimer: I am in no way related to that seller, but I may become addicted to his prices
He's also selling smaller lots for 4 C$..... and he has a good feedback
Salas said:
Cool then. I would test a regulated PSU on a next tube amp build. Not near. But that would be 250mA @ 400V. I hope that someone will build a strong one for a power amp so we will know if it scales well by then.
I'm actually very hopeful of this design's scalability. I think it's possible, but I would definitely 100% use a few mosfets in parallel both in the CCS and in the shunt block. I would choose strong n-channel mosfets like the 47N60 and stay well below the SOA DC line. Imagine sub 200uV ripple and fast current on demand in a power tube amp... might even sound nice
Also, the current set resistor would have to be chosen pretty accurately to avoid mishaps.
I agree with the zener on the G-S pins, for safety.
Salas said:
I think there is no need for series resistors with mosfets, there's an explanation here
http://cr4.globalspec.com/comment/137486/Re-Mosfet-Parallel
Basically the mosfet increases its resistance with temperature, so the one that gets more current, gets hotter, then higher resistance, and starts conducting less current, so others take over. I would hope this does not happen fast as to oscillate
I guess as long as they are the same model mosfets, and on the same heatsink. There seems to be a bit of a problem with the driver, because the capacitance increases with each mosfet added to the parallel schema. The question is does the driver have enough current to drive a bunch of unruly upset strong mosfets?
I'm not saying no. To be sure, clamping 12V zeners on S-G pins and small value resistors in series with the source can be added.
To the fellow that wanted a 260V/160mA, you may want to try something like this. I make no claims about this particular version, since I haven't built one yet, so do it only if you know what you're doing. No guarantees.
In this circuit I would use STW20NM60, the TO-247 package. Add clamping zeners or source resistors to taste. C3 can be omitted if it's stable, or increased a bit, 10p, or 18p, or 33p, if not stable.
To the fellow that wanted a 260V/160mA, you may want to try something like this. I make no claims about this particular version, since I haven't built one yet, so do it only if you know what you're doing. No guarantees.
In this circuit I would use STW20NM60, the TO-247 package. Add clamping zeners or source resistors to taste. C3 can be omitted if it's stable, or increased a bit, 10p, or 18p, or 33p, if not stable.
The good part is that with TO-220 NMOS there will always be no tears with a cheapo bag of them gotten surplus ebay style.
P.S. The one I have shown to him it may be workable also BTW (post#408). It does not have a Vref filter cap so to start high Vdif plus its clamped and strongly base stopped, and no trimmer to mess with.
P.S. The one I have shown to him it may be workable also BTW (post#408). It does not have a Vref filter cap so to start high Vdif plus its clamped and strongly base stopped, and no trimmer to mess with.
Salas said:The good part is that with TO-220 NMOS there will always be no tears with a cheapo bag of them gotten surplus ebay style.
Hehe, I got myself one bag of those for future burnorama experiments
Yes, agree. but I would use a few mosfets in parallel though. The transients I've seen in these HV high current circuits are scary