555 PWM Circuit 12v Lamp Dimming or Motor Speed Control

A simple useful Power control circuit can be used for 12v lamp dimming dimmer or motor 12 volt motor speed control. In the circuit diagram, the driver appears as integrated 7555, don’t be fooled, you can use the 555 timer IC. This integrated is produced by many companies. There may be name differences. It seems that NE555 is used in the already completed circuit picture.

For power control, MTP3055 N-Channel mosfet is used instead of some pc ATX power supply circuits, 3.3 volts can be used for regulating the mostets 45N03 IRFZ44 etc.

Instead of the MUR1560 fast diode connected to the Mosfetin Drain end, the rectification diode on the 12 volts in the pc power supply can be used, BYQ28 etc. For fast diode on the circuit, no heatsink is used, my advice is to use a small piece of circuit power 5 Amps 50W Operating frequency 220Hz

555 PWM Project

The 12V Speed Controller/Lamp Dimmer circuit can be used as a speed controller for a 12V motor up to 5A (continuous), or as a dimmer for a 12V halogen or standard incandescent lamp up to 50W. It uses pulse width modulation (PWM) to vary the power to the load (motor or lamp) at a pulse frequency of around 220Hz.

This basic design that uses a 555 timer IC, a Mosfet and doesn’t have too many elements. Being a simple design, it does not monitor motor back EMF to provide advanced speed regulation and has no overload protection other than fuses. However, it is a very efficient circuit and its cost is quite low.

The circuit uses a 7555 timer (IC1) to generate variable width pulses at approximately 210Hz. This drives Mosfet Q3 (via transistors Q1 and Q2) to control the speed of a motor or dim an incandescent lamp.

Source: http://www.siliconchip.com.au/cms/A_111001/article.html

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