Posted on Jul 25, 2012 9782
Circuit uses a simple RC network to produce an exceptionally shrill tone from a miniature speaker. With the parts values shown, the circuit oscillates at a frequency of 3 kHz and drives a miniature 2W speaker with ear-piercing volume. The output waveform is a square wave with a width of 150 Âµ$, sloping rise and fall times, and a peak-to-peak amplitude of 4 volts (when powered by 9 volts)
Current drain of the oscillator is 90 mA at 9 volts, and total power dissipation at this voltage is 01 watt, which is well below the 15 watts the 14-pin version will absorb (at room temperature) before shutting down.