At 18:59 14/10/99 -0700, you wrote:
>I am using a 9Vdc composite video camera with mike in my car. I was
>wondering if a DC converter to 9v like the Radio Shack version is safe to
>operate the camera from the car battery.

Certainly safe, but it might be too noisy to work.  Check the spec for the
camera, it might even work at 14V, so you wouldn't need a converter.  All
the ones I've seen are 12V though, not 9V

>Also, I need to attenuate the audio. The motor volume overwhelms the mike
>and distorts the sound. The sound and video outputs are going into a VCR. Is
>there a way I can attenuate the sound before it gets to the VCR?

It depends where the sound is being distorted, if the camera audio circuits
are being overloaded, you need to reduce the gain of the mic preamps, once
they add distortion, you can't get it out later.  If you aren't
specifically trying to record the motor sound, try a more directional
microphone, or put it closer to what you want to record.

If the distortion is at the VCR, a simple resistive attenuator (pad) would
do the trick.

More detail of your application (by private email if there is no other
interest on the list) would help in moving towards a solution...

Nigel