Pulsing LEDs

NECA Technical has previously provided information on ghost voltages that indicate a voltage is present on lighting switch wires, with the switch in the off position.

Ghost voltages can occur when an energised conductor is running in the vicinity of a de-energised conductor. This results in a capacitive coupling and a voltage is measurable in the de-energised conductor.

These voltages can also rise to a point where it is sufficient to fire the LED driver, resulting in a pulse of light through the LED. These pulses can be eliminated with the use of a filter across the switch mechanism. Your supplier will be able to supply these filters.

Members are also reminded that most modern digital multi meters are a high impedance type which are very sensitive and will pick up these voltages which can result in confusion when fault finding. There are multimeters available with a low impedance setting (LoZ) and when used will not show these ghost voltages. NECA highly recommends that this type of meter be used for any fault finding type work.