There is a fan control circuit on the Repeater Builder's web site that uses a 556 timer, or you can use the COR hang timer (from the same site) and change C2 to a 220uF electrolytic. That will give you about a minute runtime after PTT release.
Scott Madison, W1NB --- In [email protected], "drwoolweaver" <[EMAIL PROTECTED]> wrote: > > My club has several ACC controllers and none have provided for cooling > fan control. Does anyone have a simple circuit to turn on a fan with > PTT and then keep it running for xx minutes after PTT is released? > The repeater PTT line goes to ground on transmit. > > Most of the NE555 timer circuits that I have seen will not work in > this configuration. Delay on drop out. DODO. Thanks de David K5RAV >
