From: Paul Honigmann
Subject: Re: DC/DC converter for LCD Panel Meter; another question
Date: Sun, 8 Sep 2002 14:02:01 +0100
Organization: Nysalor Seminary for Unrepentant Riddlers
Reply-To: Paul Honigmann
NNTP-Posting-Date: Sun, 8 Sep 2002 13:08:30 +0000 (UTC)
User-Agent: Turnpike/6.00-S ()
Sounds like you're getting transients on the motor home's battery lines
- I'd guess, when the alternator is going or you're starting the motor?
(200 amps through the starter motor might cause a few transients, or the
Assuming your car radio isn't blowing up, it's probably nothing out of
the ordinary, so I'd suggest a tranzorb - say 15 volts - on the inputs.
A tranzorb is a very fast zener diode, there are various trade names for
the things. Or a varistor. Be careful that their leakage current at say
14V (= full car battery) is < 1 uA, you don't want to flatten the
battery when you leave the car in the garage for a month.
>do I have to add a capacitor[s] or something on the input or output? do I
>need a V.reg on the input? the documentation that came with them just showed
>12VDC in and 12VDC out, + - 20%.
I'd suggest 10 nF plus 100nF plus 100uF (the low value ones have lower
ESR and are better at filtering out high frequency noise).
Why convert 12V to 12V? I may have missed the beginning of this thread.
Does it need to be isolated or something?
By the way, when I tried to reply, my email package just slapped me on
the wrist and told me it is naughty to cross-post to more than one