I need to make a digital counter circuit which it counts to 15 minutes for my big project in my campus . When the circuit counts to 10 minutes, it will rings a buzzer. Same when it continues to 15 minutes, it will ring a buzzer again. (the circuit is for public speaking, so the speaker knows that he or she already went speak for 10 minutes and 15 minutes). We weren't allowed to use an Arduino, Microcontroller, PLCs, IC NE555, and a 4000 series CMOS IC but we were allowed to use breadboard, flip flop, decoder and 7 segments display. I'm kinda stuck here and I'm thinking it's impossible to make such a thing. Do you have any idea guys? |
by fahadnajed
October 25, 2019 |
Use 74xx TTL. Its cheap and easy for beginners. First thing is time base. Most accurate is crystal oscilator and divider. Second option could be line frequency 50/60 Hz derived from source. Third solution could be any oscilator i.e. 2 invertors and some RC. It needs ability to measure frequency and tune it up. Then frequency divide up to 5 min pulses. First pulse "forgot" and next pulses will run buzzer. |
by lotron
November 16, 2019 |
No answers yet. Contribute your answer below!
You must log in or create an account (free!) to answer a question.
Anyone can ask a question.
Did you already search (see above) to see if a similar question has already been answered? If you can't find the answer, you may ask a question.
CircuitLab's Q&A site is a FREE questions and answers forum for electronics and electrical engineering students, hobbyists, and professionals.
We encourage you to use our built-in schematic & simulation software to add more detail to your questions and answers.
Acceptable Questions:
Unacceptable Questions:
Please respect that there are both seasoned experts and total newbies here: please be nice, be constructive, and be specific!
CircuitLab is an in-browser schematic capture and circuit simulation software tool to help you rapidly design and analyze analog and digital electronics systems.