din can

din can elektor december 1980 — 12-39 din can L. van Ginderen The number of possible applications for noise emitting circuits is absolutely astounding — far too many to be listed in the available space. This is particularly true of the unit described here. Although not exactly original in concept, the can is capable of producing a din which will almost certainly leave your ears tingling for quite a while. 1 Figure 1. IC1 generates a tone which is modulated in frequency by IC2. The circuit consists of very few com- ponents which together form a "Kojak" type siren. The majority of the work is done by two (555) timer IC"s. The first (IC1) generates an audible tone whose frequency can be adjusted by means of potentiometer P1. The output of this timer is fed directly to a loudspeaker. The loudspeaker however does not emit a constant tone, as IC1 is modulated by a low frequency sawtooth waveform generated by IC2. The frequency of the sawtooth can be regulated by means of potentiomet...