I have been wondering lately:

How can I get a negative high voltage output from a flyback transformer?

If I connect the primary in reverse polarity will I get a Negative High Voltage?

What about the diodes in the flyback secondary, will they prevent the negative voltage?

(My thinking is, diodes only block current flow so a negative HV could be produced simply by reversing the primaries polarity, without having to remove the diodes, am I right?)

 

I have been wondering lately:

How can I get a negative high voltage output from a flyback transformer?

If I connect the primary in reverse polarity will I get a Negative High Voltage?

What about the diodes in the flyback secondary, will they prevent the negative voltage?

(My thinking is, diodes only block current flow so a negative HV could be produced simply by reversing the primaries polarity, without having to remove the diodes, am I right?)

Howdy:

If you need negative HV in ADDITION to the positive HV, it's a bit of a trick. If you ONLY need -HV, you can just reverse the polarity of the diode string on the output. (If this is a TV flyback system, you may need to do some simple mechanical tweaks.)

eric

 

It is a flyback from a TV, with only 1 HV output. I've heard the internal diodes are hard to remove. I'm wondering if it would even be worth trying. I know some of the older flybacks did not have diodes but I have not been able to find any.

 

Hello,

Probably the flyback transformers of black and white TV's still have seperate diodes.
A color TV most times use a tripler circuit that is molded.

Greetings,
Bertus

 

Howdy:

If you need negative HV in ADDITION to the positive HV, it's a bit of a trick. If you ONLY need -HV, you can just reverse the polarity of the diode string on the output. (If this is a TV flyback system, you may need to do some simple mechanical tweaks.)

eric

hello KL7AJ

can you please explain how to get +HV and -HV simultaneously ?
i have found this schematic but im not sure about -HV
have a look
http://members.misty.com/don/hvinvert.htm

cheers
wojwrobel

after hours of searching i found this
http://www.play-hookey.com/ac_theory/ps_rectifiers.html

the funny thing is i cant find it anywhere eals !!!! not even wikipedia....intresting.

 

Check if the other high voltage winding end that does not go to the rectifier is isolated from other windings.
If isolated that could be your -HV out if the diode cathode is grounded.