On Tue, 15 Dec 1998 13:37:06 -0800, Jan Steinman <jans@xxxxxxxxxxx>
wrote:
>To Frank's circuit, I'd like to add that you SHOULD NOT neglect the output
>capacitor, and you should use a tantalum, not an aluminum, electrolytic.
>I'd also suggest adding a 0.1uf ceramic capacitor to the input lead, since
>that one will be quite long. Put the input capacitor as close as possible
>to the IC. Because I work around RF a lot, I'd also slip a ferrite bead
>over each of the input leads.
>
>The input and output capacitors supress parasitic oscillations that can
>occur at arbitrary conditions. The circuit without caps may work fine on a
>bench with short leads and a regulated power supply, but with long leads in
>the field, maybe used near a CB radio or cell phone, or, or, or, who knows?
>Oscillation could expose your camera circuitry to nearly the full input
>voltage -- can you say $400 repair for want of $3 worth of parts? I thought
>you could! :-)
>
>: Jan Steinman <mailto:jans@xxxxxxxxxxx>
>: 19280 Rydman Court, West Linn, OR 97068-1331 USA
>: +1.503.635.3229
I agree with you Jan, that these caps are wisely added in adverse
conditions. But when using a 6 or less volt battery (and not an AC
sourced power supply) for input with no other equipment connected at
all, what can go wrong? Would the cable pick up enough noise to be
amplified by the IC to an unacceptable level? The batteries themselves
are doing well as a very big capacitor on the input side .... or
should the original Olympus 3V battery pack have a capacitor added as
well?
Please advise - you are more knowledgeable in the electronics fiel
than I am!
Frank van Lindert
Utrecht NL.
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