Re: 7824

Al Schoepp wrote:

> From: Al Schoepp <a_schoep@...>
>
> Hope somebody here can help with an electronics question. I need to
> step down 30vdc to 12vdc and 24 vdc for a the stepper driver I'm working
> on. I believe a 7812 and a 7824 chip will work for me. However the
> specs say that Vin must exceed Vout by 3 volts. When the system is
> operating that is not a problem. When I turn it off it will take a
> while for the power supply cap to drop to 0 so at some point in time Vin
> won't exceed Vout by 3v. Will this damage anything?

No. When they say Vin must exceed Vout by 3 volts, they mean for the
chip to provide a well-regulated output. What will happen is that the
output voltage will start to drop at this point. As long as the logic is set
to disable the stepper motors, it should cause no problem at all. The worst
would likely be that the motors would jiggle a bit as the logic is running
from insufficient power. But, there will be no damage.

Jon