Electronic siren circuit
Description. This is a compact electronic siren circuit based on three transistors.This circuit is suitable for in corporating with other alarm or siren projects such as burglar alarms, automatic factory sirens etc or a simple push to on alarm. The electronic siren circuit given here  is based on a complementary transistor pair consisting of Q2 & Q3 (BC557 & BC 37) wired as an astable multivibrator oscillator,which directly drives the speaker.The transistor Q1 is used to provide a full charge on... read moreUJT Organ circuit
Description. Here is the circuit diagram of a simple yet interesting mini organ based on UJT 2N 4891 (Q1). You can produce the desired sound by pressing each pushbuttons. You have also the option to set each push button to produce the desired tune you want. The circuit is based on a UJT oscillator who’s frequency is determined by the Presets R6 to R13 (one at a time) and capacitor C2. The transistor Q2 drives the speaker to produce... read more
Simple Alarm circuit
Multi-Tone Alarm This multi-tone alarm circuit will help you create a burglar alarm that will not only alert you of intruders but will also play a different tune each time an intruder comes, this makes sure that no regular intruders will have to listen to the same boring tone again and again! 🙂 Kidding aside this is a simple circuit to help you create a multi-tone alarm. As you know most alarms come in with a single tone so why... read more
Sound Generator Circuit
Scream Generator Circuit Scream generating circuit? Well actually this is a simple sound generator circuit, but of course, you can create a screaming sound with it. It has unlimited possibilities in pranks and Halloween, just use your imagination. It works like a car horn or a doorbell but intensity increases the more you keep it pressed. It produces a small sound at first and turns into a high pitched sound; like a scream! Description This is a real scream generator... read moreDual Tone Train Horn Circuit
Dual Tone Train Horn Circuit – Description A dual tone train horn simulator circuit can be made using two NE 555 timers connected in cascade. Here instead of using two NE 555 timers a single NE 556 timer is used which is nothing but cascading two 555’s in one package and each timers works independently. Switch S1 can be used to start the horn. The circuit is simple and low cost but works greatly. Circuit Diagram & Parts List... read moreDoorBell circuit using UM 66 IC
Doorbell Circuit Description Related Posts: Melody Generator using UM 66 Door Bell Circuit Using NE555 The main objective of the doorbell circuit is to convert electrical signals (input) into audio signals (output) with a single press of a switch. The circuit given below is a modified version of the Melody Generator Circuit, whose link is given above. In the previous circuit you had to keep the switch manually pressed for making the IC play the full music. Here... read more