Products > Test Equipment
Cloning the HP3325A Option 002 - HV Output
TERRA Operative:
I just finished drawing up the schematic in DipTrace.
Next step is to start laying out the PCB.
[Edit: Fixed schematic]
Jay_Diddy_B:
Hi,
I have had a quick look at the schematic.
1) R10 should be 3.6 \$\Omega\$
2) Q14 should be a NPN power transistor MJE182 or similar
HP used MJE223
3) Q15 should be a PNP power transistor MJE172 or similar
HP used MJE233
4) C9 should be 22uF 50V Electrolytic capacitor
5) Most of the small signal transistors need to be more than 40V
1853-0036 was selected from 2N3906 (probably for Vceo >60V)
1853-0042 is a 50V PNP transistor
1853-0020 is a 25V PNP transistor
I used MPS8099 and MPS8599 on the board I built.
Regards,
Jay_Diddy_B
TERRA Operative:
That'll teach me for doing it at 3am...
I'll make a revision tonight, maybe before midnight this time. :D
TERRA Operative:
Ok, I fixed up the schematic and reuploaded it in my post above, except I still am looking at easy to source transistors.
The MJE243 and MJE172 are easy, but Digikey doesn't have MPS8099 and MPS8599 as they are marked as obsolete, Mouser has them though, so it should be ok.
I wonder if the KSC945 (NPN) and KSA733 (PNP) would be ok substitutes?
vindoline:
Looks like a great project! I have an HP3325B - I suspect it would use the same board. I'll have to check.
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