• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

RING Detect

Not open for further replies.


New Member

I am trying to detect a ring and send it to a PIC18F452. I used the first circuit on the link below and getting approximately 3.85V at the output everytime the phone rings. I was getting 5V at the output when i have C2 = 10uF but the time constant formed by C2 & R1 to reduce the voltage back to zero volts was too long (1s) and causing conflict with the PIC18F452.

I changed the capacitor to a 1uF so the voltage would reduce back to zero volts in 0.1 seconds but the voltage at the "ring detect" now drops to 3.85V everytime the phone rings.

How do i keep the time constant at .1 seconds but have the ring detect voltage at 5V?. :confused:


Well-Known Member
You forgot to include the link.

Not open for further replies.

Latest threads

EE World Online Articles