The Musical Hold On for Telephone is an add-on external circuit that can be attached to the telephone to generate a melodious tune on the telephone line. The circuit allows the person on the other end to enjoy this melodious tune during the hold-on interval. To resume talking, just a simple switch needs to be flicked into the OFF position. A Red LED included in the circuit indicates that phone line is on-hold and it automatically turns OFF when the music stops. No. of ICs used: 1
Things which you can learn:
*Application of the melody generator IC UM66.
*Application of diodes for rectification and voltage regulation.
*Application of transistors for amplification and switching purposes.