- Joined Apr 11, 2022
I've tried powering this circuit with 2 configurations: one with 120vac where the power module (RAC03-05SK) converts it to 5vdc, 600mA, and another with 24vac (from a transformer) connected to a full bridge rectifier + a DC/DC stepdown (EPM78V2-05R0-01R0R, 5vdc, 1A). The circuit with the power module works (as I adjust the potentiometer the relay switches from NC to NO) with a 24vac hydraulic actuator I tested.
As I was switching between 120vac to 24vac to test the circuit, I forgot to connect the power module to 120vac (85-264vac input voltage range based on spec sheet) and left it at 24vac. I saw that the output with the power module was still 5vdc and the circuit was producing the desired result. Is it appropriate to a power module below the input voltage range? Is there a power module that takes in 24vac up to 120vac or so?
In the 24vac configuration with the DC/DC stepdown, I still get the 5vdc output, but as I adjust the potentiometer the voltage of the DC/DC stepdown drops to as low as 2.5vdc or so. I don't get this issue with the power module. I'm not entirely sure why this is happening, but ideally I would like to get this circuit to work with a 24vac source where the full bridge rectifier + DC/DC stepdown powers the rest of the circuit.
R1 and R2 were used to coincide with the humidity sensor output voltage (0% RH = 0.1652*Vsupply, 100% RH = 0.7952*Vsupply)