Electric Arc Lighter

Overview

An electric arc lighter generates a high-temperature plasma arc, a ionized column of air between two electrodes, that ignites gas, candles, or loose kindling without flame. Because the ignition mechanism is an electric arc, not a chemical flame, the lighter works in wind and at high altitude where oxygen is thin. The device is sealed against water ingress, making it suitable for camping and marine use.

The core innovation is a resonant step-up converter that transforms the battery's 3.7 V into a 4–8 kV pulse applied across a 2–3 mm air gap. When voltage exceeds the air breakdown threshold (~3 kV/mm), free electrons are accelerated by the electric field, collide with air molecules, and ionize them. This creates a conducting plasma channel, and current surges through, depositing tremendous energy density. The plasma glows white-hot and ignites nearby fuel by thermal conduction and radiation.

A simple MCU debounces the push button and enforces safety limits. When the user holds the button, the MCU repeatedly fires the arc at ~100 Hz. If the button is held for more than 10–15 seconds, the MCU cuts power to protect the battery and switching transistor from thermal stress.

How it works

On power-up, the MCU initializes the charging circuit and monitors the LiPo cell voltage via the fuel gauge IC. The status LED displays green (charged) or red (low battery).

When the user presses the button, the MCU checks battery voltage. If it exceeds a safe minimum (typically 3.0 V), the MCU enables the HV converter. The converter operates as a resonant boost topology:

1. A gate driver switches a high-side power MOSFET at 400–600 kHz (determined by the LC resonant tank).
2. As the MOSFET turns on, current ramps through the primary winding of the step-up coil, storing energy in the ferrite core.
3. As the MOSFET turns off, the collapsing magnetic field induces a high voltage in the secondary winding.
4. A HV rectifier diode (rated for kV) clamps the peak voltage and charges an output capacitor to ~4–8 kV.

The resonant tank tuning ensures voltage is maintained at the target arc-strike level (typically by sensing the secondary voltage and adjusting the switching frequency). When voltage reaches ~4 kV, it appears across the positive and negative electrodes in the arc chamber.

At 3 kV/mm gap spacing, the 2–3 mm air gap breaks down. Electrons are pulled from the negative electrode (cathode), accelerate through the gap, ionize air molecules, and electrons are injected into the positive electrode (anode). A self-sustaining plasma column forms, carrying 10–50 mA of current. The heat generated by this current and ion recombination melts the air to plasma state, glowing white-hot.

The user brings a cigarette, candle, or fireplace kindling into the arc. Heat from the plasma ignites the material. The arc remains active as long as the button is held and the converter supplies power.

If the button is held for >10 seconds, the MCU firmware disables the converter by stopping the MOSFET gate signal. This terminates the arc and prevents the transistor junction from reaching destructive temperatures. The user can press the button again immediately to re-strike.

The battery pack includes a protection circuit that cuts power if the cell voltage drops below 2.5 V (over-discharge) or exceeds 4.3 V (over-charge). The charging IC on the USB module regulates input current to ~500 mA and top voltage to 4.2 V nominal. Full recharge takes roughly one hour from empty.

The anodized aluminum casing is corrosion-resistant and provides EMI shielding for the high-voltage converter and arc circuit. Ventilation slots near the arc chamber allow heat dissipation. The gasket seals around the USB port and button keep moisture out, achieving IP67 rating when the cap is closed.