Door bell circuit using NE555

jacky January 27, 2014 24 Comments
Description. The main part of this doorbell circuit are two NE555 timer ICs.When some one presses switch S1 momentarily, the loud speaker sounds a bell tone as long as the time period of the monostable multivibrator built around IC1. When the switch S1 pressed, IC1 is triggered at its pin 2 and output pin 3 goes high for a time period previously set by the values of POT R4 and POT R5.When the output ofIC1 goes high it resets...
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Electronic siren circuit

admin April 7, 2010 5 Comments
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...
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UJT Organ circuit

admin February 16, 2012 11 Comments
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...
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simple multi tone alarm circuit

Simple Alarm circuit

admin November 2, 2018 1 Comment
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...
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scream generator

Sound Generator Circuit

admin November 2, 2018 1 Comment
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...
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Dual Tone Train Horn Circuit

jacky November 10, 2018 3 Comments
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...
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DoorBell circuit using UM 66 IC

admin November 9, 2018 29 Comments
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...
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Melody generator circuit

Melody Generator using IC UM66

jacky October 17, 2018 27 Comments
Melody Generator Circuit This is a simple project using the IC UM66. UM66 has an inbuilt beat and tone generator. This IC, with its three legs, looks like a transistor. This IC has many versions for playing different songs/beats. This project is suitable for beginners as its circuit is very simple. Description  The  UM66 series are CMOS IIC’s designed for using in calling bell, phone and toys. It has a built in ROM programs for playing music. The device...
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Security Alarm Circuit With High Power Siren

admin October 23, 2018 10 Comments
High Power Siren Security Alarm Circuit Description In this article, we have designed a transistor based security alarm circuit with a high power siren that can be used to provide security for homes or as a warning for intruders trespassing. Only the basic design is provided in the circuit. You can check for advanced security alarm circuits using Arduino and Micro-controllers in the links given below. Related Topics Sensitive Intruder Alarm Circuit Burglar Alarm Using 8051 With SMS Alert...
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Tone Generator – Ding-Dong Bell using IC 8021 and Transistors

jacky October 15, 2018 6 Comments
A simple “tone generator” is a cool circuit that everyone must build in their electronics learning process. We’ve designed this tone generator circuit using 8021 IC, two transistors (BC548 or C8050), a small speaker and some associated components. As you see, components are minimal and you don’t need to spend more than a small amount to buy all the required parts for this project. Let’s Build our Simple Tone Generator Here we present a simple and low cost tone...
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