Hi all,
I was design a intelligent relay board using microcontroller
AT89C52, array NPN transistor(ULN2003) and optocoupler(MCT6).
but that is fail design, because relay that already ON, can OFF randomly.
any bodhy here help me, to show circuit or a way to design a good
relay board for controlling a inductive lamp (Neon) 220VAC/120Watt.
thanks before and sorry my english is poor
You need to change two things. First, use an opto coupled AC switch device like a triac. Fairchild makes these along with many other sources. Secondly, use an external logic storage circuit, like a flip flop, to drive the opto input. This way the load will stay on when the central processor is off doing something else.
flatulent,
many people tell me that triac can not drive inductive load (triac good for resistive load). but i'll still look fairchild site, hope found something good that i need.
thanks flatulent