Simple Polyphonic DoorBell Circuit Diagram

Here is an AC triggered Multitone, polyphonic doorbell. It gives eight melodious tunes for 2 minutes. On each press it will give a new tone which will continue till the melody is over. The circuit is too simple and battery operated It uses the popular melody generator IC UM3481.

The circuit uses the popular melody generator IC UM3481. It generates music tones like Jingle bell, Santa clause is coming, Silent night, Holy night, Joy to the world, Rudolph, Red nosed reindeer, Merry Christmas, O come, All Ye faithful, Hark and the herald angel sing.UM 3482 generates 12 music tones. Capacitor C1 and resistor R2 are the oscillation components. Pin1 can be triggered either by DC or AC. Here low voltage AC is applied to the trigger pin 1 through R1 and D1. The circuit works off two pen cells which last for more than one year

Polyphonic Door Bell Circuit Diagram

Caution:The circuit is connected to high volt AC. Do not touch any parts when it is powered to avoid lethal shock

AC187 Pinout

Comments

Digital Fan Regulator Circuit Diagram

This is the project of Digital Fan Regulator Circuit diagram. The circuit presented here can be used to control the speed of fans using induction motor. The speed control is nonlinear, i.e. in steps. The current step number is displayed on a 7-segment display. Speed can be varied over a wide range because the circuit can alter the voltage applied to the fan motor from 130V to 230V RMS in a maximum of seven steps. The triac used in the final stage is fired at different angles to get different voltage outputs by applying short-dura-tion current pulses at its gate. For this pur-pose a UJT relax-ation oscillator is used that outputs sawtooth waveform. This waveform is coupled to the gate of the triac through an optocoupler (MOC3011) that has a triac driver output stage. Pedestal voltage control is used for varying the firing angle of the triac. The power supply for the relaxation oscillator is derived from the rectified mains via 10-kilo-ohm, 10W series dropping/limit-ing...

24 Hour Timer

Description: These two circuits are multi-range timers offering periods of up to 24 hours and beyond. Both are essentially the same. The main difference is that when the time runs out, Version 1 energizes the relay and Version 2 de-energizes it. The first uses less power while the timer is running; and the second uses less power after the timer stops. Pick the one that best suits your application. Notes: The Cmos 4060 is a 14 bit binary counter with a built in oscillator. The oscillator consists of the two inverters connected to Pins 9, 10 & 11; and its frequency is set by R3, R4 & C3.The green Led flashes while the oscillator is running: and the IC counts the number of oscillations. Although it's a 14 bit counter, not all of the bits are accessible. Those that can be reached are shown on the drawing. By adjusting the frequency of the oscillator you can set the length of time it takes for any given output to go high. This output then switches the transistor; which in turn o...

Using the SG3525 PWM Controller Explanation and Example Circuit Diagram Schematic of Push Pull Converter

PWM is used in all sorts of power control and converter circuits. Some common examples include motor control, DC-DC converters, DC-AC inverters and lamp dimmers. There are numerous PWM controllers available that make the use and application of PWM quite easy. One of the most popular of such controllers is the versatile and ubiquitous SG3525 produced by multiple manufacturers – ST Microelectronics, Fairchild Semiconductors, On Semiconductors, to name a few. SG3525 is used extensively in DC-DC converters, DC-AC inverters, home UPS systems, solar inverters, power supplies, battery chargers and numerous other applications. With proper understanding, you can soon start using SG3525 yourself in such applications or any other application really that demands PWM control. Before going on to the description and application, let’s first take a look at the block diagram and the pin layout. Pins 1 (Inverting Input) and 2 (Non Inverting Input) are the inputs to the on-board error amplifier. If you a...

ffd

Search This Blog