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Subject: 
Re: Solar-powered RCX?
Newsgroups: 
lugnet.robotics
Date: 
Tue, 10 Nov 1998 17:15:05 GMT
Viewed: 
2524 times
  
Tom Boles wrote in message <36486EB4.3941EC00@intellisens.com>...
Sorry, maybe there is to much engineer in me but are you saying the external power
supply produces low voltage AC and that it is rectified in the brick to DC to run
the system? I can believe it's regulated inside, but it needs DC from the "wall
wart", not AC.



Many embedded systems use a bridge to be polarity and AC/DC insensitive on
the power inputs. At the very least, you should put a series diode to protect
against reverse voltage.

By adding a bridge (or just 4 discrete diodes) you drop about 1.4V from the
supply, so 9 V only gets about 7.5 to the motors using MOSFET drivers, while
a 12V supply and regulator should work fine and supply full 9V to the motor
outputs.

This may explain the dying battery effect when using an adapter and batteries
at the same time. If the adapter is less than about 10.4V, the batteries
would get used up to the low voltage point of the adapter. It that about
as clear as mud?

Has anybody measured the output from the wall wart?....

Cheers,

Ralph Hempel - P.Eng

------------------------------------------------------
The train stops at the train station,
The bus stops at the bus station,
So why am I sitting at a work station?
------------------------------------------------------
Reply to:      rhempel at bmts dot com
------------------------------------------------------



Message has 1 Reply:
  Re: Solar-powered RCX?
 
Ralph Hempel <rhempel@bmts.com> wrote (...) Someone should tell Sony this - a friend fried my discman by reversing polarity. I had (foolishly) assumed that they would have dne this on the 9V external PS feed. Doh. Moz (26 years ago, 12-Nov-98, to lugnet.robotics)

Message is in Reply To:
  Re: Solar-powered RCX?
 
Sorry, maybe there is to much engineer in me but are you saying the external power supply produces low voltage AC and that it is rectified in the brick to DC to run the system? I can believe it's regulated inside, but it needs DC from the "wall (...) (26 years ago, 10-Nov-98, to lugnet.robotics)

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