High Voltage Coin Cell
3 days ago
- #Electronics
- #Joule Thief
- #DIY
- Tore down a bistable LCD display but blew up the PCB during experimentation.
- PCB generates around 27 volts from a coin cell using a mystery IC.
- Decided to fix it by building a Joule thief circuit.
- Joule thief circuit is simple and can generate high voltages with minimal current.
- Initial circuit uses a 10K base resistor and a series resistor to limit current.
- Output includes a 27V Zener diode, a small capacitor, and a 1M bleed resistor.
- Used two 1mH inductors for the coils, achieving good results.
- Circuit successfully outputs 27V, enough to clear the bistable display.
- Current draw is around 10mA when the button is held, suitable for a coin cell.
- Theoretical estimate: 40-50,000 button presses per coin cell.
- Created a regulated version with another transistor for better efficiency.
- Regulated circuit has an average current of 1.53mA, making it very efficient.
- Full exploration available in a linked video.