It is clear in datasheet that you can give AC or DC input to this opto-insolator. Pins 2 and 3 is input DC volts and pins 1 and 4 is for AC volts input. pin 8 is Vcc and its max absolute rating is -0.5 V to +20 V but recommended voltage is +2 V to +18 V. If you are interfacing it with MCU which works at 5 V then give +5 V for Vcc pin of opto. Pin 7 has no connection. Pin 5 is Ground. Pin 6 is Vo i.e., Voltage output pin whose range is -0.5 V to +20 V and it should give an output of 0V to 5V if you need to interface this pin with MCU. The opto has inverted output i.e., if input is high Vo is low and if input is low Vo is high. A 0.1 uF capacitor should be connected between pins 8 and 5. It is mentioned that Vin ie.n pins 2 and 3 (dc V input) max rating is -0.5 V. I don't know if it is correct or not. It is not mentioned in the datasheet whether 230 V AC/DC can be given to AC/DC input.
I simply want to tell my pic chip that a pump motor is running and has 230 volts at it.
I have a HCPL-3700 chip optocoupler
I have a pic 16f877A microcontroller
I don't understand the datasheet which is why I am asking for professional help on the matter.
I simply need to know how to connect the 230 volts side of the HCPL-3700 ie can I connect 230 v ac straight to the chip or do I have to drop it somehow ?
If somebody could post a simple diagram I would be most grateful
Yes this is what I am talking about, I just need a circuit to drop the voltage to an acceptable level for input, I think the Zero crossing circuit is wrong for me though.
But I am only a beginner and I can't quite get my head around that graph, it looks as though I need a capacitor and a couple of resistors on the ac side but I am not quite sure how to work it for 230 volts..
Thanks
Rizzy
EDIT:
I have just had another look at the graph, would it be 100k ohms for 250 volts AC so about 90k ohms for 230 volts then divided by 2
and that is the value for each side ?
As calculated in the application note, the filter capacitor raises the threshold to about 300 VAC (RMS) with 100k external resistance, means the optocpupler will never switch with 230 VAC. The resistors should be reduced to about 30k/0.5W each.