Solenoid valve controller

[jok8r]

Hi

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?

Or how can i achieve this?

 

[Boncuk]

Hi,

24V AC or DC valve solenoids draw considerable current (P=10W, at 24V I=0.42A). They can neither be driven by an OpAmp nor by a timer IC.

You should use driver triacs or transistors depending on the supply AC or DC.

A decimal counter will switch a single solenoid (again with driver) per output.

Using a diode network at the counter outputs you might switch any desired combination of solenoids.

Boncuk

 

[crutschow]

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.

 

[user_88]

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.