A digital stop watch built around timer IC LM555 and 4-digit counter IC MM74C926 with multiplexed 7-segment LED display.MM74C926 consists of a 4-digit counter, an internal output latch, npn output sourcing drivers for common cathode,
7-segment display and an internal multiplexing circuitry with four multiplexing outputs.The counter advances on negative edge of the clock. The clock is generated by timer IC LM555.The circuit works off a 5V power supply. It can be easily assembled on a general-purpose PCB. Enclose the circuit in a metal box
with provisions for four 7-segment displays, rotary switch S1, start/stop switch S2 and reset switch S3
Testing
First, reset the circuit by pressing S3 so that the display shows ‘0000.’ Now open switch S2 for the stop watch to start counting the time. If you want to stop the clock, close S2. Rotary switch S1 is used to select the different time periods at the output of the astable multivibrator (IC1).
8 comments:
so this circuit din involve any programming part?
Sorry you can't programme this circuit.
is it can be practically implimented???????????
do this circuit need some programming??? or can just buy the parts and join them together according to the circuit n straightaway can be use??
No need to programme this circuit
i completed the project but problem is that it count upto 99 second instead of 59 please tell me solution through my mail muhammadshernasir@gmail.com
can you post PCB layout of digital stopwatch
Sure,We'll post it soon