This electronic horn circuit is a very simple and easy to construct horn circuit that can be used for bikes or some other vehicles or applications .
This electronic horn circuit use only one gate of a 4093 quad 2 input NAND Schmitt trigger , connected in a low frequency , square –wave oscillator circuit .As you can see in the circuit diagram the output of the oscillator ( pin 3) drives the gate of Q1 transistor and the drain of the IRF511 FET drives a small horn speaker . The output frequency of the horn’s output can be modified by adjusting the R1 potentiometer .
For this simple horn circuit you need to use a 12 volts regulated power supply circuit .
This electronic liquid detector circuit diagram is based on the ULN2429A monolithic bipolar integrated circuit designed for detecting the absence or presence of many different types of liquids . The ULN2429 electronic liquid detector circuit can be used in automotive , home or industrial applications .
The absence or presence of the liquid is determined by comparing the loaded probe resistance (probe immersed in the fluid ) with an internal or external resistance . At the output you can connect a LED , incandescence lamp , loud speaker or even such relays or solenoids, but just I you connect at pin 12 a capacitor , to provide a dc output ( typically the output signal is a square wave ) .
If you need to connect at the output a device that need more than 30 volts you can use the ULN2429A-1 which is identical , but support devices with operation up to 50 volts .
Main features of the ULN2429A are : high output current , AC or DC output , single wire probe , low external parts require , reverse voltage protection , internal voltage regulation .
This fluid detector electronic circuit need to be powered using a power supply that provide an output voltage between 10 and 16 volts .
This siren alarm circuit diagram is based on a specialized IC UM3561 , which is a low power CMOS LSI specially designed for this type of applications . The UM3561 siren alarm contains all needed parts ( oscillator , selector circuits , programmed mask ROM ) to simulate siren sound using few external components .
The siren circuit require a power supply circuit around 3 volts and has a low current . The UM3561 siren sound generator circuit has possibility to generate four types of sounds : police siren , fire engine siren , ambulance siren and machine gun sound .
The transistor used in this project must be 2SC9013 , 2SC8050 or similar type .
The speaker used at the output must have 8 ohms impedance and a 0.2 watts power .
As you can see in these three circuit diagrams , the configuration for the siren is very simple . Police siren , fire engine siren , ambulance siren and machine gun sound .
Police siren , fire engine siren , ambulance siren .