So I came back to this thread to reread the advice on ballasts. How does impedance in series to a load limit current? Is it acting like a resistor? Don‘t resistors draw more current?
Sorry still not getting it,
Ben
Any impedance, whether it is a resistor, inductor or capacitor in series will almost always reduce the current.
A resistor will take current from a supply. An electric heater is a resistor, and if I plug in more heaters, more current is taken, but that is putting the heaters/resistors in parallel, not series.
When a resistor is in series with a load, the current will be reduced. Cars have heater fans that have variable speeds, and the fans are often made to run slower than full speed by putting resistors in series with the motor. The more resistance, the less the current, and the slower the fan runs. The control just connects different resistors for different speeds.
The ballast has inductance, so when connected to ac mains, that has an impedance. If the inductor were connected directly to the mains supply, the current flowing would be the mains voltage divided by the impedance, and the designer can chose the inductance to give however much current is required.
If the fluorescent lamp is in series, the current will be a bit, but not much, less than that, and the amount of current is mainly controlled by the design of the ballast, the mains voltage and the mains frequency.