Schematics > Security and other sensors and detectors > Melody generator for greeting cards
Melody generator for greeting cards
This tiny circuit comprising of a single 3 terminal IC UM66 can be built
small enough to be placed inside a greeting card and operated off a single 3V
flat button cell.
There is not much to the circuit. The UM66 is connected to its supply and its
output fed to a transistor for amplification. You can either use a 4ohm speaker
or a " flat" piezoelectric tweeter like the one found in alarm wrist watches.
If you use the piezo, then it can be connected directly between the output pin 1
and ground pin 3 without the transistor.
The UM66 looks like a transistor with 3 terminals. It is a complete miniature
tone generator with a ROM of 64 notes, oscillator and a preamplifier. When it
first came into market, it was programmed for the "Jingle bells" tune. Now they
come with a wide variety of different tunes.
Title: Melody generator for greeting cards
Source: www.electronic-circuits-diagrams.com
Published on: 2005-02-01
Reads: 355
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