hello everyone..i am doing a project on water heater control using 8051. Can anyone tell me how to interface 8051 and geyser(water heater) through a contactor/relay?? My doubt here is 8051 is low voltage output and geyser is a high current device. So how should it be done??
A Mains-Powered Load can be controlled by a microcontroller in two different ways:
- microcontroller -> optocoupler -> triac
or
- microcontroller –> transistor -> relay/contactor
or combination of the above ..
thank you both!! as bassa improved the circuit i shall first find out what our apparatus needs and understand whatevr components u have suggested of and then make a query with you thank you
Added after 11 minutes:
AND just one more doubt before i start off.. I am not understanding the concept that how much voltage ouytput is an atmel 8051 delivering out? and on what grounds should i understand the coupling of all the devices because the geyser is a current controlled device and 8051 supplies voltage puilses as low as 15ma:| so could you please explain that to me li what is the concept behind this part of coupling??
Added after 4 hours:
and ya mr.Ian.P i read from archives which is on this linh which i think you posted in 2004 :!: .. got a clear cut info of the components and i read about the triac triggering also.. so now the clarification i need is whether i could connect 8051 to MOC3021 and then triac BT137 or SC141D and then hook it to the geyser?? i matched the trigger current levels and so on and found matching but waitin for your confirmation ofcouse fuse also i shall include as u said.