I've been trying to build few AC switches and tried using pc817s and they worked perfectly when i built a single switch with it but as soon as i attach another switch both switches turn on at the same time. I'm using an isolated supply for pc817 and few diodes to stop any reverse current in pc817.
Can anyone tell what have been doing wrong or any alternate method to use pc817 with triac(BT136).
Thanks.

 

A circuit diagram would help.
You can switch a triac with a PC817 if you have a separate supply of about 5V referenced to the same voltage as MT1 on the triac.

 

hhere is the diagram of my circuit.

 

What is the device labelled + and - ?
Identify the terminals on the opto and the triac, and we might get somewhere.

 

That "device" is a battery. 5v
The dot on pc817 is anode.
You can find the pin diagram anywhere.
BT136 Terminal connected to PC817 is GATE next to it is T1 and other is T2

 

That "device" is a battery. 5v
The dot on pc817 is anode.
You can find the pin diagram anywhere.
BT136 Terminal connected to PC817 is GATE next to it is T1 and other is T2

Correction terminat next to gate is T2 and 3rd one id T1