12 Aug
2002
12 Aug
'02
7:37 p.m.
At 06:54 PM 8/12/02 +0100, you wrote:
Failing that, if you can find the right connector
(possibly from another
TI calc PSU) the TI-59 requires 6.2V 200mA AC.
I always wanted a TI-59, but I have to make do with a -58...
You can probably build something with epoxy/rubber and a couple
of pins off a female DB-25 connector..
A word of caution: if you are going to build a charger with a 6.3V
transformer, keep in mind that the chargers that TI provided
for this and other calculators had very high secondary winding
resistances; I just measured mine, and it is 16 ohms. I have
no idea about the reactance, though.
The high resistance in effect limits the maximum current across
the rectifier diodes and battery. I suspect that if you connect
a < 3ohm transformer something might burn.
carlos.
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Carlos E. Murillo-Sanchez carlos_murillo(a)nospammers.ieee.org