Thanks Guys this looks good. I'll give it a try and let you know how it goes.
Just 1 question though, what would be suitable transistors to use for Q1-4?
Thanks Guys this looks good. I'll give it a try and let you know how it goes.
Just 1 question though, what would be suitable transistors to use for Q1-4?
For NPN Q3 and Q4, any NPN with Vceo >50V and IC >0.5A can be used.
For PNP Q1 and Q2, you'll need a transistor with Vceo>100V and IC double of that used by both the relay coils together. So if each relay use 0.2A, you'll need a PNP that can switch IC>0.8A.
Where do you source your components? If you checks part numbers that are available to you and posts back, people around here can decide for you.
One question, what do you intended to use for the 12V power supply?