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555 Timer Circuits

This section of EG Labs brings you some interesting electronic projects and circuits based on 555 Timer IC. These 555 timer based circuits and schematics are a good reference to learn and understand the basic timer circuits.
Latest 555 Timer Circuits

Simple Stepper Motor Driver

The circuit presented here rotates stepper motor and varies its RPM (speed). It does not use any micro controller (or micro processor) or any programmable digital device also it does not require any software program to generate sequence of pulses. It drives stepper motor using simple, easily available and commonly used components and ICs like IC555, decade counter, OR gate, current driver chip etc. That is why the name given simple stepper motor driver.

The circuit presented here counts from 00 to 99 and displays it on two seven segment displays. It can work as free running counter in auto mode or it can count manually when button is pressed. In auto mode it gets continuous pulses and counts continuously at a rate of 1 Hz. That means the count is updated at every second or in other words counter displays time in seconds. This counting rate can be changed by changing pulse frequency. In manual mode, the count is incremented when push button is pressed manually. So it can be used to count up to 100 (from 0 to 99) as per manual requirement.The counter circuit is made up of decade counter cum display driver chip CD4026. The pulse circuit is build using IC555. The circuit can be used in many applications like object counter, frequency counter, RPM counter, stop watch timer, token count display and many others.

Many devices require input pulses for their operation. Some device requires continuous train of pulses some requires single pulse. In some of the devices there is a provision to alter between continuous pulses and single pulse. For example a stepper motor controller can have two operating modes – auto and manual. In auto mode it requires continuous pulses to rotate motor continuously while in manual mode it requires single pulse to be generated when button is pressed manually.

The circuit presented here is 2 in 1 circuit that generates low frequency pulses in the output. It has two operating modes. In auto mode it generates pulses continuously and in manual mode it generates pulse when push button is pressed. The circuit is built using single IC555. To generate continuous pulses it is configured in astable mode and to generate single pulse it is configured in monostable mode. 

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