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An IC two tone siren

2017-08-03 03:22  
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This article is an introduction to integrated two tone siren. Master the principle is very effective method is to combine text read schematics. This  circuit is interesting for children, can be mounted on bicycles, electric cars and motorcycles, also depends on the model and a variety of games and toys. SW1 positioned as shown in circuit diagram with typical dual tone sound of police or firefighters car produced by the oscillation, IC1A and IC1B Gates. SW1 is set to another position, the old siren sounds, and then slowly increase the frequency reduced, thereby reproducing the P1 starts to oscillate in IC1C and IC1D. Speakers from Q1, should be reasonable in size and packing, in order to obtain a more realistic and sound output. Tone and paragraphs sound vibrations can be different by changing the values ??of C1, C2, C5, C6, and / or associated resistors. There is no power switch is required: leave SW1 in the low position (old siren) and the circuit consumption will be negligible. This circuit is simple but effective. 


Circuit diagram:

Siren circuit diagram


R1,R3___470K   1/4W Resistors
R2______680K   1/4W Resistor
R4_______82K   1/4W Resistor
R5______330K   1/4W Resistor
R6_______10K   1/4W Resistor
R7_______33K   1/4W Resistor
R8________3M3  1/4W Resistor

C1,C5_____10μF  25V Electrolytic Capacitors
C2,C6_____10nF  63V Polyester Capacitors
C3_______100nF  63V Polyester Capacitor
C4_______100μF  25V Electrolytic Capacitor

D1-D3___1N4148  75V 150mA Diodes

IC1_____4093   Quad 2 input Schmitt NAND Gate IC

Q1______BC337   45V 800mA NPN Transistor

P1______SPST Pushbutton

SW1_____DPDT Switch

SPKR____8 Ohm Loudspeaker

B1______6V Battery (4 AA 1.5V Cells in series)




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