18 May
2009
18 May
'09
1:06 a.m.
On 17 May 2009 at 16:51, Andrew Lynch wrote:
Hi! Does anyone know of an available transformer
suitable for making
an S-100 power supply? I need 120VAC input and 10VAC output and +/-
18VAC outputs.
Hi Andrew,
I'm not certain if the S100 linear PSU transformers were eve a
standard item. The voltages are strange enough not to be common.
The transformer in my Integrand box is certainly a custom job. MITS
certainly used 2 transformers.
FWIW, the Stancor P-6138 transformer used in the MITS Altair 8800 was
a 7.5VCT unit and the 133P5 was something like 12.6VRMS. Less diode
drop, the voltage on a capacitor-input filter, will approach
1.4xVRMS, so even with a 12.6VRMS transformer, you've got plenty of
headroom for the regulators. If your supply voltage is too high,
you'll pay for it in excess heat in the series (analogue) regulators.
Cheers,
Chuck