Re: Two more silly II questions...

[Roger Johnstone <roger@roger.geek.nz.removethisbit>]

In <RLadnZE_2O8pq1DbnZ2dnUVZ_gSdnZ2d@comcast.com> glen herrmannsfeldt  
wrote:
> zwsdotcom@gmail.com wrote:
> 
>> 1. Is it possible to power a IIc directly off 12VDC with nothing else
>> in between battery and computer? 
> 
> Power inverters are pretty reasonably priced these days.
> 
> The first stage of most switching power supplies converts
> the input to 300VDC.
> 
> Otherwise, you could try to run an analog regulator off the
> 12V input to generate 5V.  Most linear regulators want a 2V
> margin.  Do you really mean 12V battery?  If so, it might be
> good enough to run the 12V line directly.  A power inverter
> running a switching power supply is probably more efficient.

The Apple IIc uses an external power brick (just a simple transformer 
and rectifier) to provide about 15 volts DC. This is fed into the IIc 
where a switching supply produces the required voltages. The IIc can 
happily ran directly from a 12V battery. According to the Apple IIc 
Technical Reference Manual the internal switching power supply can run 
anywhere from 9V to 20V and consumes a maximum of 25 watts, or 2 amps at 
12 V.

-- 
* Roger Johnstone, Invercargill, New Zealand -> http://roger.geek.nz
* PS/2 Mouse Adapter for vintage Apple II or Mac
* SCART RGB video cable for Apple IIGS