Sunday, November 25, 2012

Remote Telephone Ringer

This remote telephone bell ringer allows you to use a large (and loud) external bell in place or in addition to the built in (and rather wussy) ringer in most modern telephones. This is ideal for large outdoor areas, noisy shops or those hard of hearing. Most any large bell can be used as the circuit can be easily adjusted for various supply voltages.

Schematic

Schematic for remote telephone ringer

Parts

Part
Total Qty.
Description
Substitutions
C110.47 300V Capacitor 
C2147uF 25V Electrolytic Capacitor 
R111K 1/4W Resistor 
R2110K 1/4W Resistor 
R311K Pot 
R412K 1/4W Resistor 
Q116A, 200V TRIAC 
Q216A, 200V SCR (106, Etc.) 
D111N4774 Zener Diode 
D2, D321N4007 Rectifier Diode 
U114N33 Opto Isolator 
BELL1Large Bell (Fire Bell, School Bell, Etc.) 
MISC1Board, Wire, Socket For U1, Case

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