Timer | Electronic Project Circuits

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Timer set for 30 minutes by transistor

This circuit is based on learning of the discharge and charge of the C, which can be used as a timer circuit and can be applied in the off electrical appliances. The application has also put relay instead of LED can be enabled.
When you click the switch S1 will cause LED1 light told state ready to run S2 is a timer switch. On press switch S2 current will flow to the C1 charge fully. Then to discharge out through R2 to limit current flow to the bias for transistor Q1. Q1 and Q2, which work together to Darlington Compound. To have growth rates high to drive the LED2 light over time as C1 discharge all Q1 and Q2 stops LED2 is off if you want the timer circuit is longer. Then add the C1 and if you want a little time. to reduce it to C1.

Be the first to comment - What do you think? Posted by admin - June 18, 2010 at 8:56 am

Categories: Timer Tags: basic timer, led delay timer, Timer, timer clocks

PIC16F628 Digital Clock Timer

This clock timer uses a PIC16F628 microcontroller to display 3 and 1/2 digit time and control an external load. It can be programmed to time from 1 to 59 minutes. The clock includes a calendar with leap year and optional daylight savings adjustments. The timer output can be set from 1 to 59 minutes and manually switched on and off. The clock also has a correction feature that allows an additional second to be added every so many hours to compensate for a slightly slow running oscillator. The oscillator uses a common 32.768 KHz watch crystal and the frequency can be adjusted slightly with the 24pF capacitor on the right side of the crystal.

Source:http://ourworld.compuserve.com/homepages/Bill_Bowden/pic_ck.htm
Thank You.

Be the first to comment - What do you think? Posted by admin - February 1, 2008 at 8:55 am

Categories: Microcontroller, Timer Tags: Clock timer, Microcontroller, pic-microcontroller, PIC16F628, Timer

24 Second Shot Clock by IC digital

Circuit :Milardo de Guzman
Email :Milardo de Guzman

Description:
This is a circuit intended to be used in basketball shot clock.

24 second shot clock

Notes:
To start in 24 seconds; 24s LOAD SW and Reset SW should be push simultaneously. If not, the count will start in 99. Pulse input can be connected to 555 astable multivibrator but must be calibrated for real time clock. The PAUSE SW must have a Switch Debouncer so that the counter will count normal when counting is paused and then turn-on.

When the count reach 00, the NOR gate will have an output of logic1 that will turn on the two transistor. The buzzer will rung and light will turn on. The two transistors are continuously turn-on not until LOAD SW and Reset SW is push. All have a +5v power supply.
source : http://www.zen22142.zen.co.uk/Circuits/Timing/24ssc.htm