If the light on an air conditioner (AC) flickers when it's turned off but not while it's running, it could be due to a phenomenon called residual current or ghost voltage. Here's an explanation of how this can occur:
Capacitance: Air conditioning units typically have electrical components such as capacitors. Capacitors store electrical energy and can exhibit a phenomenon called capacitance, where they retain a charge even after the power is disconnected. This residual charge can cause a small amount of current to flow momentarily, which may be enough to cause the light to flicker briefly when the AC is turned off.
Induction: Another possible cause of the flickering light is electromagnetic induction. When the AC is running, it generates an electromagnetic field as part of its normal operation. This electromagnetic field can induce a current in nearby electrical wiring or other conductive materials, including the wiring that powers the light. The induced current can be weak and may not be sufficient to light up the bulb noticeably. However, when the AC is turned off, the electromagnetic field collapses, and the sudden change in the magnetic field can induce a slightly stronger current in the wiring, causing the light to flicker.
It's important to note that these phenomena typically result in very low levels of current and pose no safety risk. Flickering lights in this context are generally harmless and do not indicate any significant electrical issues. However, if you have concerns about electrical safety or notice any other unusual behavior, it's always advisable to consult a qualified electrician to evaluate the situation.