I’m new to electronics and am trying to ground myself in basic concepts. On my test circuit board I have a 5.08V power supply, a 200 ohm resistor and a 1.5V incandescent lamp in series. The voltage drop over the resistor measures 5.05V and the voltage drop over the lamp measures .02V. The current measures .02A. Why doesn’t the lamp have more voltage available to it? Thanks!
The cold resistance of your lamp is only around 1 Ohm. As such most of the voltage is being dropped over the resistor.
If you want to drive the lamp from 5v you need to measure the hot current through the lamp at 1.5V so you can calculate the hot resistance. Knowing that you can select the right size of resistor. Be aware it will be small and will need to be high wattage.