I'm doing a project and need to build a system with solenoid valves, but I have very little knowlage of electronics. I need a circuit that can control 1 to 4 solenoid valves. The valves need to either be open for a certain time each be be contolled by switches.
I'm using 24V ac valves and I've read that I can run them on DC as well, I got a circuit from a friend that uses a 555 timer with a 4017 decade counter, he said I could maybe modify that and use op amps at the outputs to get the required voltage. Is this possible?
If you drive an AC solenoid with DC, you will likely need to lower the voltage (or add a series resistor) to provide the required current. Without the AC impedance generated by the coil inductance, the current will be higher for a given DC voltage as compared to the same AC voltage.
A solid state relay will probably have a sufficient current capacity to operate your AC relay.
There are SSRs which will operate from a +5 V source, and can be switched from TTL level voltages. There are other SSrs which have a wider range of switching voltage. Often, you can find various SSRs, in good condition, at surplus stores and markets.