HF finals from PC monitor boards?
I already found something, thinking a bit sideways: these SS devices
impressed me more on the current- than on the voltage handling side.
I reckoned that scaling to higher powers was mostly done in current,
so I headed for a low power video unit I had: a long deceased bible-
sized 1970's TV + radio combo, with a 2" B/W screen. As suspected, I
found 2-3W low capacitance bipolars that could run into VHF... so
much so I had to bead them to keep them from producing spurs in my
ugly prototype.
On Jul 30, 11:37 pm, Chris Jones wrote:
2SB772 (PNP) and 2SD882 (NPN) (10-Watt 30V, 3A, fT80MHz)
The video amplifiers in a monitor have to be pretty fast for high resolution
signals, and often these are discrete transistors to handle the power. I
got some 2SC2682 devices out of monitors - 180V, 3.2pF, fT=200MHz, 10W - a
few of these could make a useful amount of RF, I reckon.
Hmmmm.... I'll look harder. The pile of monitors is still there
gracing a hidden nook of my place.
W.r.t. the high definition requiring high frequency: KVM switches
often quote their bandwidth, which must match what^s required from a
given definition (if a KVM only quotes that, and not pixels, good luck
finding the equivalents). Bandwidths now run in the 200-300MHz range,
which is a good omen.
Where would such transistors be?
In the vicinity of the HV coil?
Or near the CRT cathode?
|