Four-tone siren

EE July/August 1986 20four-tone siren This interesting little circuit is par- ticularly aimed at modellers. Based on just one IC, it is easy to make and it is inexpensive. Moreover, it operates from a 3 V battery, and con- sumes only 150 pill in the quiescent state, and 28 mA in operation. The four different tones are selected by two switches, Si and S2. The table correlates the switch positions and the produced sound. (St) 3V 46 Si S2 Sound Police siren Fire tender Ambulance Staccato