How would I get a relay to operate with the ringing voltage on the phone line Rick
Ringing Voltage from Phone
Dec 05, 2008
3 Replies
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start with a relay having about 1800 ohms coil resistance operating voltage 12V DC hook that to the DC side of a bridge (can use 1n914 diodes etc) and put a 250v 1uf capacitor in series with the AC terminals of the bridge
should work. REN approximately 1.
If the relay chatters put a shottky diode in parallel with it. if that doesn't help enough put a capacitor there too.
if you measure over-voltage on the relay coil use a smaller capacitor
You have to detect 90 volts ac. Not hard to do.
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