What about quiescent current for additional pairs? Must 1ohm and 0.5ohm resistors need to be adjusted for extra current? Have you any ideal quiescent current value for each pair?
Mr terranigma,
Pl refer to your post # 1877 where in you have simulated High power Hexfet version of Circlophone. I intend to build one with 55-0-55 V DC supply and IRFP240 as output gear.
For CCS I intend to use MPSA42 in place of 2N5550 which has 500ma current rating. Only problem seem to me is their low Hfe. Could you suggest other suitable transistor as well. Some where in previous post you have suggested to change this transistor due to heating problem.
Pl refer to your post # 1877 where in you have simulated High power Hexfet version of Circlophone. I intend to build one with 55-0-55 V DC supply and IRFP240 as output gear.
For CCS I intend to use MPSA42 in place of 2N5550 which has 500ma current rating. Only problem seem to me is their low Hfe. Could you suggest other suitable transistor as well. Some where in previous post you have suggested to change this transistor due to heating problem.
I don't remember that I have mentioned any heat problem for this particular transistor. I didn't notice such an issue with this one. You can use any small transistor here as long as they have a safe Vce margin (minimum 2*Vs).
Good luck with high power Circlophone. Bear in mind that you have to use some hefty heatsinks with good thermal connection with mosfets.
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Some people say that small plastic transistors (TO-92) are OK for up to 100mW.
Quick sim I just did, shows that with 55V rails, ccs transistor will dissipate 150mW of heat (schematic from post #1743).
That's too much, so the answer is NO - small plastic TO-92 transistor may not handle it.
I would use TO-126 transistor (e.g. MJE340)
Quick sim I just did, shows that with 55V rails, ccs transistor will dissipate 150mW of heat (schematic from post #1743).
That's too much, so the answer is NO - small plastic TO-92 transistor may not handle it.
I would use TO-126 transistor (e.g. MJE340)
>I just measured the temperature of my CCS transistors and they are barely at 50*C
Yeah, that's perfect.
With my ccs (1 transistor, 2 resistors, 2 diodes), it was running too hot.
Here is another ccs (attached), with 2 transistors - only 78mW at 55V rails. Small TO-92 will do.
On the same schematic, Q13 seems to run at 117mW. Could be too hot...
Yeah, that's perfect.
With my ccs (1 transistor, 2 resistors, 2 diodes), it was running too hot.
Here is another ccs (attached), with 2 transistors - only 78mW at 55V rails. Small TO-92 will do.
On the same schematic, Q13 seems to run at 117mW. Could be too hot...
The dissipation rating of TO92 transistors varies between 200mW and 1.3W depending on the type.
In general, if the surroundings are not excessively hot, half the rated power is safe enough.
Of course, one is always free to adopt more generous margins.
Cooler devices = increased reliability
In general, if the surroundings are not excessively hot, half the rated power is safe enough.
Of course, one is always free to adopt more generous margins.
Cooler devices = increased reliability
Not to my knowledge.
There are kits sold in India and Philippines (and possibly elsewhere), though
Is "Circlophone©" a copyrighted design? Have you any patent for its design principles? I'm asking this for curiosity. In what conditions you'll permit that it becomes a commercial product? I guess producers might have to contact with you for settling on a legal agreement.
I suggest you to test 2N5550/2N5551/MPSA42 first since you will build the one with zener as mine. There is chance for getting a similar result as mine. If you feel discomfort with heat, you can replace it with some bigger ones as Minek suggests.
I have already a working HEXFET C with Cascode transistor KSA1381 on 32-0-32 Dc working perfectly. So I want to add CCS also for my higher power HEXFET version. I have already modified my PCB according to one transistor CCS as suggested my Mr Elvee. I think I will sellte with MJE340 as CCS transistor.
Attached. If - as Elvee suggested - that TO-92 transistors are good for at least 150mW, than all the transistors in this schematic should work fine.
No need for TO-126.
