Re: Regulating High Voltage

From: Jonathan Kirwan (jkirwan_at_easystreet.com)
Date: 11/15/04 

Date: Mon, 15 Nov 2004 16:42:46 GMT

On 15 Nov 2004 12:14:58 GMT, Roger Johansson <no-email@home.se> wrote:

>"Mike" <mike@notemail.com> wrote:
>
>> It seems a zener diode is the way to go, but I can't find any that
>> will regulate 400V (only 200V).
>
>Take two.
>
>Two diodes in series, add the zener voltages.

I'm not sure how good that will be. The 1N5281A is rated at 200V @ 650uA but
it's tolerance is 10% with some .11%/C temperature drift, on top. I suppose the
OP could hand select them to get the right voltage, though.

Also, since the Izt of the 1N5281A isn't anything like the 10mA desired, a BJT
emitter follower would be needed that only requires some percentage of that
650uA biasing, say 100uA (it's .16V change for 65uA change in bias, which is
probably fine.) This means beta of 100, which may be achievable so long as
there is at least a volt or two drop across V(CE). But how much the V(CE) will
have to stand off could be a problem. The MJ12005 is mentioned in the Art of
Electronics, 2nd ed., as an NPN with Vceo of 750V, though. Also, that same book
includes a couple of high voltage circuit examples on pages 369 and 370 that
could be used for something like this. The second example regulates the ground
return.

Jon

Relevant Pages

  • Re: Sustitute for Standard Cell. Why Physicists cant deliver!
    ... I would make or buy low voltage, zener diode, power supplies. ... It's a STUDENT lab fer cripes sake! ... google and a search for lesser standards. ...
    (sci.physics)
  • Re: Zener diode modeling
    ... Also say that voltage is about 9 volts. ... is that zener or avalanche breakdown? ... the breakdown is by avalanche. ... Searching on the exact phrase ""Zener diode oscillation" will do it. ...
    (sci.electronics.design)
  • Re: Sustitute for Standard Cell. Why Physicists cant deliver!
    ... I would make or buy low voltage, zener diode, power supplies. ... It's a STUDENT lab fer cripes sake! ... google and a search for lesser standards. ...
    (sci.physics)
  • Re: Using 12v lights on a 6v system
    ... My voltage is swinging from about 3 volts at idle to over 12 at ... The battery was in there to light the tail light, ... Suzuki had a tiny little voltage regulator on their TS200 around 1966. ... I suppose it was also a zener diode that grounded out the excess ...
    (rec.motorcycles.tech)
  • Re: TECH: data east star wars (no +68 volt from power supply) dmd is dead
    ... I'm assuming you know it's not fuses and you have a voltage coming in and measurable on the banded side of D5 with respect to GND. ... 1N4760b 68v zener diode D9 ... replacing TR1 then TR3. ...
    (rec.games.pinball)