I am using a 12VDC Linear Actuator the Actuator runs by reversing polarity so I want to use one Momentary switch
push one time to go up and again to go down does anyone have a circuit to do this please help
Here's an idea. It uses a latching relay to remember the polarity and to provide the voltage inversion. Each time you press the button, it flips to the opposite polarity.
The circuit uses four diodes (1N4001 or similar), two 470 ohm resistors, two 330 uF 16V electrolytic capacitors, and one varistor for overvoltage protection.
What is the initial inrush current of the actuator?
That is already a small relay, you could certainly locate smaller ones but you are really splitting hairs at the end of the day unless there is a necessity for it to be smaller?
Yes, you can use a smaller relay. If your actuator draws 0.3A I would use a relay rated for at least 2A though.
You should also change the values of the capacitors and the resistors, according to the coil current consumption. The relay I originally suggested draws 50 mA on each coil, and I specified 330 uF capacitors and 470 ohm resistors. You should reduce the capacitors and increase the resistors in proportion to the reduction in coil current. I've marked recommended values below.
Good stuff KrisBlueNZ,
I had a similar requirement not long ago, and spent some time figuring out logic arrays and driver trannys to do the job.
I could of just used a relay as per your design. But years of "solid state is the only way" made my brain cells ignore the old school electro-mechanical solutions.
Thanks again, schematic saved for future reference.
I put it together and it does not work I did see that the Relay is one coil with a center tap with a center is postive when I push the button I get 9.66VDC Than 0VDC I attached a pic of the relay layout this is the one your listed 8amp 12VDC F12-ND/1128677 can you please help
I wouldn't use a PCB for such a simple circuit unless you want to do a production run.
For simple projects like this, stripboard is ideal. If you're in England, it's called Veroboard.
You can get it from Mouser (see http://nz.mouser.com/ProductDetail/...EpiMZZMvJBlHRSOGUxHYmn%2bCGy5OpyeFTLS%2bcHp8=) or any electronics hobbyist store. The Mouser one is FR4 fibreglass; you can get the SRBP type more cheaply.