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BD243 DIY Mini Tesla Coil Prototyping Kit
BD243 DIY Mini Tesla Coil Prototyping Kit
High-Voltage Wireless Power Demonstration – Build Your Own Spark Gap Tesla Coil
Introduction
The BD243 Mini Tesla Coil Kit is a DIY prototyping set that lets you build a functional tabletop Tesla coil using the BD243 power transistor. This educational kit demonstrates wireless power transfer through resonant inductive coupling and produces impressive electrical arcs.
Key Features
High Voltage
Generates 50,000+ V arcs
DIY Assembly
Complete through-hole components
Wireless Power
Demonstrates resonant coupling
Educational
Learn high-frequency AC principles
Kit Contents
| BD243 Transistor | 1x Power NPN transistor |
|---|---|
| Primary Coil | 3-turn thick copper wire |
| Secondary Coil | 800-turn enameled wire |
| Capacitor Bank | 4x 0.1μF 1kV ceramic caps |
| Spark Gap | Adjustable screw terminals |
| Base Board | Pre-drilled prototyping PCB |
| Power Supply | 12V 2A DC input |
| Toroid | Aluminum foil covered sphere |
Technical Specifications
| Input Voltage | 12V DC (2A minimum) |
|---|---|
| Resonant Frequency | 200kHz-1MHz (adjustable) |
| Secondary Coil | 800 turns, 28AWG enameled wire |
| Arc Length | Up to 2cm (depends on tuning) |
| Transistor | BD243C (60V, 6A) |
| Dimensions | 100mm diameter × 150mm height |
| Safety Features | On/off switch, insulated base |
Assembly Instructions
- Prepare the Base: Mount all components on the prototyping board
- Wind Secondary Coil: Carefully wind 800 turns of enameled wire around PVC pipe
- Assemble Primary: Create 3-turn spiral coil from thick copper wire
- Install Capacitors: Solder four 0.1μF capacitors in parallel
- Mount Transistor: Attach BD243 to heatsink with thermal paste
- Connect Spark Gap: Adjust screw terminals to 1-2mm initial gap
- Add Toroid: Secure aluminum-covered sphere to top
- Final Check: Verify all connections before powering
Schematic Diagram
Note: This is a basic Slayer Exciter circuit using the BD243 transistor as the oscillator
Tuning Procedure
- Power on with 12V supply
- Adjust spark gap to 1mm initially
- Observe if arcs form at toroid
- If no arcs, slightly increase gap
- For maximum output, adjust primary coil taps
- Fine-tune by moving primary coil up/down secondary
- Optimal tuning occurs at loudest buzzing and longest arcs
Safety: Always use insulated tools when adjusting while powered
Safety Precautions
High Voltage Protection
- Never touch components when powered
- Keep flammable materials away
- Discharge capacitors after power-off
Electronic Safety
- Use proper heatsinking for BD243
- Ensure adequate power supply (12V 2A+)
- Check for shorts before powering
Operational Limits
- Limit continuous operation to 2 minutes
- Allow cooling between demonstrations
- Monitor transistor temperature
Troubleshooting
No Arcs
- Check spark gap adjustment
- Verify secondary coil continuity
- Ensure proper primary-secondary orientation
Weak Output
- Increase input voltage (up to 15V max)
- Optimize primary coil positioning
- Check capacitor bank connections
Transistor Overheating
- Improve heatsink attachment
- Reduce duty cycle
- Verify proper base resistor value
