"The phone is a remarkably complex, simple device,
and very rarely ever needs repairs, once you fix them." - Dan/Panther

Main Menu

will any diode do?

Started by Babybearjs, December 07, 2022, 07:10:34 PM

Previous topic - Next topic


I'm in the process of setting up diode ringing and need to know what diode is supposed to be used? will any diode work? or are they like resistors, and have certain values that need to be followed. I understand that I need to bypass the capacitor in the phones as the diode replaces that function. any help is appreciated....


I have no clue about diode ringing  ;) but  a diode is a "valve" that lets electrons pass only in one direction.
What you normally get today are silicon diodes, which are quite robust. They are classified by the current capacity in forward direction and the allowed inverse voltage. In the forward direction there will be a voltage drop of 0.6 or 0.7 Volts. This is a material property of silicon.
A very common type would be 1N4007 for 1 A and 1000 V, but many many other suitable types exist.
Formerly, selenium rectifiers were often used in telephone and radio applications, but they are no longer made. They are doing basically the same job but the characteristic curve is different, the forward voltage drop starts around 0.4 V but rises over 1 V when the current increases, heating up the element more.



yeah, I looked at phils video about it already.. quick question is, does this work on regular land lines, or is the diode ringing dedicated to ringing voltage from the PSU only.... I have 3 landlines coming in and 10 extentions I'd like to setup on this system if it can be done....


I don't know, some exchanges does allow you to use a diode instead of the capacitor, but none of mine.

Whats happening if you need a common ground for the ringers is even more complicated so that will probably need a lot of thinking before you are finished ;)


These should work - 1N4005 also a 446F was  used back in the day.
Craig Stanowski


One trick that you can do is add a one diode to one of the buzzer pairs in the phone. This will make the sound of the buzzer different and sound like a burp.