The internal resistance of the source is responsible for the low current.

Source voltage = 5.15 V

Current limiting resistor value = 220 Ω

Current = 0.00029 A

Total resistance in circuit = 5.15/0.00029 = 17759 Ω

Internal resistance of the source = 17759-220 = 17.5 kΩ

The internal resistance of the source is responsible for the low current.

Source voltage = 5.15 V

Current limiting resistor value = 220 Ω

Current = 0.00029 A

Total resistance in circuit = 5.15/0.00029 = 17759 Ω

Internal resistance of the source = 17759  - 220 = 17.5 kΩ

The internal resistance of the pulsing source is responsible for the low current

Source voltage = 5.15 V

LED current = 0.00029 A

Total resistance in circuit = 5.15/0.00029 = 17759 Ω

Internal resistance of the source + LED resistance* = 17759-220 = 17.5 kΩ

(* Yellow LED forward voltage of 2V at 20 mA cannot be directly factored in).

The internal resistance of the source is responsible for the low current.

Source voltage = 5.15 V

Current limiting resistor value = 220 Ω

Current = 0.00029 A

Total resistance in circuit = 5.15/0.00029 = 17759 Ω

Internal resistance of the source = 17759-220 = 17.5 kΩ