Introduction: Dual-Tone Horn

This is a circuit used for making a horn with dual sounds which are produced simultaneously. the horn can be used for Bugler alarms and Vehicles.. this circuit consists of few components used are commonly available in any electronics shop and are cheap.

Step 1: Parts List

R1,R3                ----   4.7KΩ
R2                      ----   56KΩ
R4                       ----   68KΩ
R5                       ----   220Ω
R6                       ----   2.2Ω
R7                       ----  1Ω
VR1,VR2,VR3    ----  10kΩ Preset
C1,C2                  ----  22nf ceramic - EIA code (223)
C3,C7,C10          ----  100nf ceramic - EIA code (104)
C4, C11,C12       ----  10nf ceramic - EIA code (103)
C5                        ----  10uF 35V Electrolytic cap
C6                        ----  470uf 35v Electrolytic cap
C8                        ----  220uf 35v Electrolytic cap
C9                        ---- 1000uf 35v Electrolytic cap
sW1                     ---- Switch
IC1                       ---- LM556 Or NE556
IC2                       ---- TDA2003 heat-sink (aluminum piece of minimum size(20mmx10mmx1mm) or buy a standard heat-sink)
SP1                      ---- 4 Ω  1W Speaker
CCB1                   ---- Common Circuit Board

Step 2: Circuit Diagram

Assemble the components into the CCB according to the circuit diagram VR3 controls the volume of the Horn. VR1 and VR2 varies the sound (tone) of the horn. I got this circuit diagram from internet, this looks complex but it is a simple circuit. i will try to make  an another layout of the circuit diagram soon.. Try to use an IC socket so that you can solder easily and prevent IC from Burning. And if there are mistakes in your soldering and while connecting it to the 12v DC supply, the IC is shorted or damaged, then you can change the IC easily and is way better than De-soldering everything..electrolytic capacitors with voltage rating range from( 20v to 65v )can be used in the circuit.And add a heat-sink(aluminum piece of minimum size(20mmx10mmx1mm) or buy a standard heat-sink from electronic store) to the TDA2003 IC or it will overheat and burnout

Step 3: Conclusion

Hoping this circuit helps you all in various ways and uses as required.. and be careful while using soldering iron and try to use IC holders which will prevent the IC burning off due to heat from soldering iron and the IC can be removed if there is an IC failure..and dont forget to rate this instructable if you like it..