Telephone Ring Indicator Using LED Lamp
This is the circuit for Telephone Ring Indicator Using LED Lamp. The telephone ring is typically 90VAC RMS so is more than enough to light a single LED. C1 is used for DC blocking thus no OFF-HOOK condition at standby state. R1 is to dissipate excess voltage, while D1 and C2 rectifies it to positive DC voltage. D2 regulates the voltage to 9VDC with R2 again limits the current of the LED during ringing.
posted by Regulus Berdin at 11:13 PM
5 Comments:
i am learning a lot from you! thanks!
about this circuit i test it with MultiSim9 and it doesn't work! the signal for LED is very low to power it!
i remove C1 and R1 and replace C2 with 4.7mF and then it works!!
if i add just C1, the circuit doesn't work! why??!! C1 is a DC-blocking capacitor so why it do like that?! also i think R1 is too big!
(i use a 90V-60Hz-AC source for telephone line)
thanks for your time and sorry for my English
this is so nice post i like this a lot. i learn a lot of knowledge. you are to good man.
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It only lit the led for 1 second, then the phone keep ringing and nothing... it worked for a while but stop now
thanks!
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It only lit the led for 1 second, then the phone keep ringing and nothing... it worked for a while but stop now
thanks!
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