How to Glow a Light Bulb with a Battery and Switch
The full build video for this simple DC circuit — the steps below follow the setup process in the same order.
What you need before starting
- Power Source: 3.7V Lithium-Ion / LiPo flat battery or 9V battery
- Light Source: Low-voltage DC light bulb and screw-terminal bulb holder
- Control: SPST Rocker Switch
- Wiring: Connecting wires (red for positive, black for negative)
The full build video for this simple DC circuit — the steps below follow the setup process in the same order.
Identify component terminals
Lay out the battery, bulb holder, and rocker switch on the workspace. Identify the positive (+) and negative (-) terminals on the battery and the two contacts on both the switch and bulb holder.
Connect negative wire directly to bulb
Connect the black negative (-) wire coming from the battery directly to one terminal on the bulb holder.
Connect positive wire through the switch
Connect the red positive (+) wire from the battery to one terminal pin of the ON/OFF rocker switch.
Connect switch output to bulb holder
Run a second red wire from the remaining terminal pin of the rocker switch to the open second terminal on the bulb holder to complete the series circuit.
Test circuit operation
Flip the rocker switch to the ON position to close the circuit and illuminate the light bulb. Flip it back to OFF to break the current flow and turn off the light.
If something does not work
Bulb does not light up: Verify that wire ends are securely twisted or clipped to the terminal posts without loose contacts.
Switch is bypassed (bulb stays lit): Ensure the positive wire is split across the switch terminals rather than connected directly to the bulb.
Light is very dim: Check battery voltage; low-voltage batteries will not fully illuminate higher voltage rated bulbs.