Re: [CAD_CAM_EDM_DRO] Re: Parallel port power increase

Mariss Freimanis wrote:

>Randy,
>
>1.5V doesn't sound right at all for an output. It does sound about
>right for an input though.
>
>Are you using a scope to read the output? A voltmeter will average a
>digital output to its mean value. Try toggling the direction output;
>a meter will give a truer reading then.
>
>If you read 0V and 5V then it's a true TTL output. If it reads 0V and
>3.3V then it is not and will need a buffer.
>
>

The problem is he is trying to SOURCE current to a very high current
opto-coupler, that needs about 15 mA to turn on.

Jon