Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

330 volt pass transistor

Status
Not open for further replies.

truenoteno

New Member
i will give u a background of what i have done..

I stripped out the AC part of a 200w AT computer power supply to eventually put a computer in my car (my 1000th attempt).
I tried making power supplies from regulators for the mainboard because it worked for my hub. (unsuccessful)
Now, I have measured the output of the bridge rectifier and it's 330 volts
Why not use a transformer to reduce the voltage ?
Anyway, I have come to the conslusion that I need to supply around 300DCV at around 750mA.

I have found this circuit:
https://www.rowan.sensation.net.au/electronics/stepup.html

I have replaced the diode with a zener, everything works fine. I looked in my "Dick Smith" catalogue, the aussie equivalent of "Radio Shack" for a high voltage zener but unsuprisingly no luck. Are they manufactured at all ?

If u can't then I'll have to wind a very long coil... :( and it won't be as stable

how can I impement a pass transistor on the above circuit ?
I tried a similar method to which voltage regulators use with no luck
 

plot

New Member
i'd say get a 120v power supply, and work on converting 12 volts from your car battery to 120 volts for the computer psu.

you can buy adapters for your car to switch 12 volts to whatever is needed, they are often sold so people can put playstations and whatever else in there car.
 

plot

New Member
well then, i'm sure there are high voltage zener diodes.. but lacking any, i found this article --> https://www.tubecad.com/december99/page18.html , which skimming through it i found might be helpfull.

the problem with finding a high voltage zener, is even though i know they exist up to at least 400v, i have no idea where to get them in australia.
 

tavib

Member
:twisted:
Use of a zener diode(or generally a parallel stabilisation) is not a good idea, because of high power disipation involved.
In your parivate case, the flyback switching source, the output voltage is dependent by output load, if the output is open then the voltage will rise uncontrolled(limited only by power loses in transistor and coil), and the circuit can be damaged.
The usual and economic way to do the flyback source stabilisation is to control the width of conduction pulse applied to transistor function of output voltage on capacitor.
Some IC are special developped for this purpose, or a custom circuit can be make for this.
 

plot

New Member
tavib said:
:twisted:
Use of a zener diode(or generally a parallel stabilisation) is not a good idea, because of high power disipation involved.
In your parivate case, the flyback switching source, the output voltage is dependent by output load, if the output is open then the voltage will rise uncontrolled(limited only by power loses in transistor and coil), and the circuit can be damaged.
The usual and economic way to do the flyback source stabilisation is to control the width of conduction pulse applied to transistor function of output voltage on capacitor.
Some IC are special developped for this purpose, or a custom circuit can be make for this.

it's a car though, so power wouldn't be a problem... not like it's gonna run up the electric bill ;) heat might come into play somewhere though...
 

Nigel Goodwin

Super Moderator
Most Helpful Member
truenoteno said:
I have found this circuit:
https://www.rowan.sensation.net.au/electronics/stepup.html

I have replaced the diode with a zener, everything works fine. I looked in my "Dick Smith" catalogue, the aussie equivalent of "Radio Shack" for a high voltage zener but unsuprisingly no luck. Are they manufactured at all ?

I don't see as that simple circuit is going to provide 300V off a 12V supply, also replacing the rectifier by a zener isn't going to work either, it wouldn't provide any stabilisation in that position.

If you search back through the threads, I posted a circuit for a 12V PC PSU a while back.
 

truenoteno

New Member
Nigel Goodwin said:
truenoteno said:
I have found this circuit:
https://www.rowan.sensation.net.au/electronics/stepup.html

I have replaced the diode with a zener, everything works fine. I looked in my "Dick Smith" catalogue, the aussie equivalent of "Radio Shack" for a high voltage zener but unsuprisingly no luck. Are they manufactured at all ?

If you search back through the threads, I posted a circuit for a 12V PC PSU a while back.

can u send me the link for your previous post on 12v car psu's ?
I can't find it, I think it got deleted over time...


thankyou
 

stevez

Active Member
When vacuum tubes were used in mobile radio equipment power supplies had to develop the voltages you describe. It was common for amateur radio equipment to be constructed so that the high voltage/filament supplies were on a separate chassis for various reasons. For portable or mobile operations it was common for the amateur to construct a supply to convert 6 vdc or 12 vdc to deliver the high voltages needed. I recall at least one solid state version that appeared in the 1968 or 1969 Radio Amateur's Handbook - someone was tossing the books out so I grabbed them. You might find what you need by researching some amateur publications of that era and by checking with amateur radio operators in your area. Updating and old, proven design might be a solution.
 

Sebi

Active Member
I think, the safe solution to keep the original supply, and to build a simple 12VDC to 220AC 400Hz inverter.Just don't forget switching the power input to 220 position on PSU.
 
Status
Not open for further replies.

Latest threads

EE World Online Articles

Loading
Top