Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
Hi
This is shankar
with this i have attached a circuit that controls the switching of electrical appliances using dtmf(double tune multi frequency) signals as control signals.
please help me by giving ur suggestion about how the ckt works
It looks to me like the 555 is wired as a comparator, the electrolytic capacitor on the feed from the opto-isolator suggests to me that it won't pass any DTMF frequencies, and is more likely to be simply passing the ringing pulses. Everything else in done in software, presumably counting the number of rings to turn the selected relay on?.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
