[time-nuts] Anybody want a Thunderbolt power supply?
csteinmetz at yandex.com
Wed Aug 31 17:12:13 EDT 2016
> with the venerable 2n3055 (1960s!) as the series pass device, and an
> exotic TIP29 (my 1985 databook has it, but the original datasheet says
> 1968) to drive it..
> They probably used the 1970s versions of the transistor, of course,
> since the 723 didn't come out til early 70s..
Fairchild introduced the orginal 723 (the µA723) in 1968. I think
National brought out the LM723 within the year, but can't swear to it.
While the schematic I posted shows a TIP29 driver transistor, that was
for a different, 3A supply. The lower-current +/-12v supplies in the
HTAA-16W-A do without the driver, and connect the 3055 directly to the
723 output (which can source up to 150mA). The schematic I posted also
shows foldback current limiting, which the +/-12v supplies in the
HTAA-16W-A do not have.
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