Simplistic MosFET HV Shunt Regs

[merlin el mago]

I got other one 2SK170V Idss 11.66

 

[Salas]

No good. Look to get more J309 as that design shows you can even parallel. But also get a few J112, J113 which are cheap and low noise. The may come handy to you.

 

[merlin el mago]

I have 2SK3577 but are SMD.

 

[Salas]

Those are mini Mosfets. Don't.

 

[merlin el mago]

Ale Moglia used in his gyrator & CCS PCBs. CCS PCB – Bartola(R) Valves

 

[merlin el mago]

Are N channel JFET https://www.mouser.es/datasheet/2/308/2SK3557-D-1801840.pdf

 

[Salas]

There was a NEC switching MOSFET with the type 3577. I saw that. For 3557 JFET its OK.

 

[merlin el mago]

Thanks Salas, let's see how to convert SMD to through hole.

 

[merlin el mago]

Worse max. 7.2mA without SSHV2

 

[merlin el mago]

I ordered some SOT23 to DIP adaptors to measure the Idss of 2SK3577 that I have on hand.

 

[merlin el mago]

Made some measurements:

CCS SSHV set to 500mA + CCS load set to 11mA each channel
Ripple AC 51mA

CCS load set to 11mA each channel without SSHV2
Ripple AC 43mA

 

[Salas]

What do you mean AC current ripple? At what point of circuit you measure that and with what?

 

[merlin el mago]

Between the anode of tube & ground. True RMS DVM.

 

[Salas]

So mV not mA. Does it have a frequency? Is it 50Hz? DMMs have Hz function.

 

[merlin el mago]

Yes sorry AC is V not A. Yes have Hz function. It's Demestres made by Mastech.

 

[Salas]

Nice DMM but better use the scope for watching kinds of noises.

 

[merlin el mago]

How to use the scope?

 

[Salas]

AC coupling and 10x probe setting. Same test points in circuit as for DMM. Tweak vertical sensitivity and horizontal time scale knobs until catching the noise fish.

 

[merlin el mago]

Scope set 5mV/cm 0.5us 10x probe setting.

 

[merlin el mago]

Same set up only change 1x probe setting.