Re: transformer question

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Mike Harrison by way of Terry Fritz <twftesla-at-qwest-dot-net>" <mike-at-whitewing.co.uk>

On Mon, 17 Sep 2001 08:12:37 -0600, you wrote:

>Original poster: "Carlo Latasa by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<carlo23-at-pacbell-dot-net>
>
>Computer monitors have the same circuitry as a TV as far as a Flyback
>Transformer
>it's drive circuitry. The result is a High Voltage output that varies any
>where from
>15kV to 35kV depending on the size of the screen. The output signal is not
>really a
>sinewave and therefore has many other higher frequency components, but the
base
>frequency is usually on the order of 20-60kHz. 
They usually have internal diode multipliers, which will output
pulsing 'DC-ish' - I  think they rely on the tubes capacitance to
provide most or all of the output smoothing 
>I would imagine the current
>capability to not be much more than 100 micro amperes. Keep in mind that is
>usually
>best to remove only the flyback transformer and the drive transistor (if
>you can
>find it now-days) then create your on drive circuit.

I've found it's usually easier to use a mosfet for drive, as the
transistors typically used in TVs & monitors are hard to drive due to
low gain. Also, you will often want to use a drive winding other than
the original primary, to make it easier to run from a low voltage DC
source- TVs/monitors typically drive the primary from a HT supply of
100V or thereabouts.
Flybacks usually have a number of windings, used for things like
providing low-voltage auxilliary supplies, and these often make good
primaries for low-voltage use.