Archive for the ‘Timer Circuits’ Category

How to Work With 32K crystal and AVR Microcontroller

This article teaches you how to add 32K external crystal source to  AVR micro controller (Atmega8 ) with circuit diagram & C program. Introduction Timing-is one of the basic function, performed by the micro controllers. Every microcontroller has at least one timer/counter module in its architecture.  However if the counter is clocked internally a few issues may arise in some cases. Sometimes the clock frequency may not stable, or sometimes the clock frequency may be too high than necessary. Sometimes external clock is required to have the required quality. To solve these problems, some AVR micro controllers comes up with…

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Selective timer alarm.

Description. A timer circuit using IC 4060 is given here. The IC 4060 is a 14 stage binary counter with a built-in oscillator.R2, R7, C1 are the components that determine the frequency of the oscillator and the outputs will become high one after other and only one at a time. The last five outputs are only used here. The high pulses from the outputs are used to trigger the NE555 IC. Here NE555 is wired as a monostable multivibrator. The buzzer will produce the alarm when the output of IC2 goes high. The duration of the alarm depends on the…

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10 Minute timer circuit.

Description. When ever you need to get an alarm or intimation after ten minutes ,the circuit shown below can be used.The circuit is nothing but  a monostable multivibrator based on IC NE 555.When ever you press the reset push button the green LED D1 glows after 10 minutes. Circuit diagram with Parts list. Notes. Assemble the circuit on a good quality PCB or common board. The time duration can be set by varying the POT R5. The switch S1 can be a push button switch. The IC1 must be mounted on an IC base.

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