View Full Version : debugging relay matrix

04-22-2007, 04:35 AM
I have some strange behavior on one of the relays in a ghost telephone keypad relay matrix: the relay in question is wired up to be switched by a 2n7000 FET. When I set the FET pin high, I get 2.12 volts or so, and it does not switch the relay. The output pin is fine. I am using the standard 10k ohm to ground on the pin and and a green LED in parallel (The LED drains a trivial amount of voltage). The FET/relay seems to be fine, since it switches as expected when tied directly to +5v. I was hoping someone might be able to tell me what to look for here.