The switch would be connected in parallel with the main power input to the inverter circuit. The output of the DC-DC converter would be connected to the LED bulb. The main power would be connected to the input of the inverter circuit and the output of the inverter circuit would be connected to the input of the DC-DC converter. A charging circuit to charge the battery when main power is available.A switch to manually select between battery power and main power.An inverter circuit to switch the bulb between using main power and battery power.A DC-DC converter (also known as a boost converter) to step up the voltage from the battery to the voltage needed to drive the LED bulb.A battery (such as a 12V lead-acid battery or a 3.7V lithium-ion battery) to provide backup power.The circuit would contain the following components: Inverter Bulb Circuit Construction Rechargeable Inverter LED Bulb Circuit Since it has an internal backup power source and electronic control circuit, it can detect the switch state even during a power cut. The features of an inverter LED bulb include fully automatic control, low power consumption, and high efficiency. It can be switched off when not required. When AC mains power goes off, this inverter bulb automatically switches on to act as a DC emergency light. This mode is used to charge the internal battery with the LED bulb off. However, most inverter LED bulbs come with a charge-only mode. The bulb is designed to charge the internal battery even during normal operation. Thereafter the charging voltage is automatically cut to protect the battery from getting overcharged. These internal batteries require three to four hours of charging time to fully charge. Most inverter LED bulbs have lithium-ion batteries that provide three- to four-hour backup. That is, when there is AC mains power, it works as a normal light bulb but when there is a power cut, it works as an emergency light bulb. Also check: Which Current is more Dangerous AC or DC?īasically, an inverter LED bulb is a two-in-one bulb.

Battery backup light bulbs