(Floating Load)
The circuit shown in figure 1 is indicated to floating loads. The resistor R in series with the zener diode is calculated using the formulas indicated in the correspondent section.
Formula
Constant Current Source - Floating Load
IL = Vz / R1
Where: IL is the load current in amperes (A)
Vz is the zener voltage in volts (V)
R1 is the resistance in ohm (Ω)
Note: Rz is calculated according the zener formulas in this site.