Phone Line to Audio Electronic Circuit

From CircuitsArchive

This circuit uses an audio coupling transformer and a capacitor.

The primary windings add in series to 500 ohms. Instead of connecting them directly together, add a cap between them. It was something like 0.047 micro farads with a 600V rating. And the secondary which is 500 ohms runs into the control room mixer.

            Tip   >------------/ II
                               / II /-------<
       (primary winding 1)     / II /
                               / II /
                  >-----X------/ II /
                        I        II /
          0.047 uF      =        II / -----CT   (secondary winding)
                        I        II /
                 >------X------/ II /          Output Side to Mixer
                               / II /                        
       (primary winding 2)     / II /
                               / II /-------<
         Ring    >-------------/ II
 

Sources

• tpappas[at]hamp.hampshire.edu