Quantity   Component name
1 × 2N3904 NPN Transistor Drives the joule thief
1 × Transformer toroid We will use it as the joule thief coil and the step up transformer
1 × 1k resistor
1 × A rectifier bridge Doesn't really matter which one - just grab one from the junk parts box!
1 × Big electrolytic capacitor Stores the charge to be released into the LED. I use a 10 000 uF 63V Cap.
1 × Solderless terminal (2-pin) It holds the LED.
1 × SPST Switch For turning the circuit on and off
1 × Coin cell holder