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Hi HangOver, if you are going to use a totally isolated battery, say a 7 amp security battery then it might work and all you would need is a few capacitors and a 78L09 ( a three pin 9 volt low power voltage regulator ).
If you have any connection between the multi meter’s battery and the vehicles electrics, including a common earth, Ron was on the money, then the multi meter will NOT read correctly and in many cases, will not work at all.
Go for analogue moving coil meters. They do not need a power source.
Aaron.
.............and you have only just figured that !!!!!! :D:D:D;)Quote:
Originally Posted by beforethevision
Quote:
Originally Posted by beforethevision
Oi! I heard that. :DQuote:
Originally Posted by ladas
Coming late to this thread, what you want is 4-5 rectifier diodes in series, which will give you a voltage drop of 0.7V/diode regardless of current. The diodes also offer some isolation, though as others state, any measurements on the power supply of the multimeter will be completely suspect regardless, and may kill the mm.
/Damien
Thank you all for your comments and suggestions but after having a chat to the resident "electronics" bloke at work he sort of confirmed what you all said, you can, but you can't and said it's way easier to just keep replacing the $2 battery and less to go wrong.
I think I agree with him, again thanks for all you suggestions.
Steve
Why would you spend $2 on a battery that will only last 2 months, when you could spend $2 on electronics that will kill your meter in 2 seconds? :p
Oh yer............. Then I wouldn't have to buy any more batteries :DQuote:
Originally Posted by damienb