This circuit produces a musical tone whenever someone touches the touch point designated as TP in the circuit. The circuit works from two AA cells and produces enough sound.
The circuit uses IC UM 3481 commonly used in musical circuits. The IC contains a ROM with 512 musical notes, tone generator, rhythm generator, modulator, run off control, oscillators, frequency divider and preamplifiers,.Â So a very few number of components isÂ required for this circuit.C1 and R1 act asÂ the timing components forÂ the built in oscillator. The transistor Q1 is used for driving the loud speaker. The base of the transistor Q2 is used as the touch point to trigger the musical bell.
Circuit diagram with Parts list.
- The circuit can be assembled on a general purpose PCB.
- Use two AA cells in series for powering the circuit.
- The speaker can be 2 W, 8 Ohm.