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Simple PWM lamp dimmer using NE555
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A simple and efficient PWM lamp dimmer using timer IC NE555 is discussed in this article. Yesterdays linear regulator based dimmers can only attain a maximum efficiency of 50% and are far inferior when compared to the PWM based dimmers which can hit well over 90% efficiency. Since less amount of power is wasted as heat, the switching elements of PWM dimmers require a smaller heat sink and this saves a lot of size and weight. In simple words, the most outstanding features of the PWM based lamp dimmers are high efficiency and low physical size. The circuit diagram of a 12V PWM lamp dimmer is shown below. PWM lamp dimmer using NE555 Circuit Diagram As you can see, NE555 timer IC which is wired as an astable multivibrator operating at 2.8KHz forms the heart of this circuit. Resistors R1,R2, POT R3 and capacitor C1 are the timing components. Duty cycle of the IC’s output can be adjusted using the POT R3. higher the duty cycle means higher the lamp brightness and lower the duty cycle...
Police siren using NE555
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Description. A lot of electronic circuits using NE555 timer IC are already published here and this is just another one.Here is the circuit diagram of a police siren based on NE55 timer IC. The circuit uses two NE555 timers ICs and each of them are wired as astable multivibrators.The circuit can be powered from anything between 6 to 15V DC and is fairly loud.By connecting an additional power amplifier at the output you can further increase the loudness. IC1 is wired as a slow astable multivibrator operating at around 20Hz @ 50% duty cycle and IC2 is wired as fast astable multivibrator operating at around 600Hz.The output of first astable mutivibrator is connected to the control voltage input (pin5) of IC2. This makes the output of IC2 modulated by the output frequency of IC1, giving a siren effect. In simple words, the output frequency of IC2 is controlled by the output of IC1. Circuit diagram. Notes. The circuit can be assembled on a Perf board. I used 12V DC for powering the ci...
Touch Switch using NE555
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The series of touch switch or touch switch is built by IC NE555, a series of touch switches can be used to turn on lights, alarms or other electronic equipment. This circuit uses 2 pieces of metal plate media as touch, MP1 (Metal Plate 1) and MP2 (Metal Plate 2). Touch switch circuit is equipped with a visual LED indicator for relay status (load active). To enable (Relay ON) can be done by touching the surface of MP1 and to turn it off by touching the surface of the MP2. MP1 and MP2 in touch this switch can use a small piece of copper (diameter 5mm) was enough. Touch Switch series with NE555. Component List 555 touch Switch R1 = 3.3M R2 = 3.3M R3 = 10K R4 = 1K C1 = 10nF-63V D1 = 1N4007 D2 = Red LED Q1 = BC547 IC1 = NE555 RL1 = 12V Relay