I want the transistor to fully trigger the SSR (V>3, I=10mA) when a current flows through the sensor. With R2 = 470 Ohms and best sensor settings (D0) I can get:
Sensor off: V(CE) = 4.57, D0 = 0.29, V(BE) = 0.29
Sensor on: V(CE) = 2.4, D0 = 1.4, V(BE) = 0.62
Sensor on not connected to transistor has D0 = 2.7V
I'm getting 2.5 V(CE) across my transistor, which should have less than 1 V in saturation according to my reading of the datasheet.
I've attempted R2 = between 400-4000 with the SSR only partially operating.
Here's my schematic:
R1 is a possibility for a constant current circuit, which I don't fully understand (currently shorted/not used).