Ringing Voltage from Phone

T

trickyrick

Guest
How would I get a relay to operate with the ringing voltage on the
phone line
Rick
 
trickyrick wrote:
How would I get a relay to operate
with the ringing voltage on the phone line
http://www.google.com/images?q=am-detector+mtmscientific
 
On 2008-12-05, trickyrick <rickj@sympatico.ca> wrote:
How would I get a relay to operate with the ringing voltage on the
phone line
Rick
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
 
"trickyrick" <rickj@sympatico.ca> wrote in message
news:e950055e-ba56-433e-a728-2ddb48cfdd68@t3g2000yqa.googlegroups.com...
How would I get a relay to operate with the ringing voltage on the
phone line
You have to detect 90 volts ac. Not hard to do.
 

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