ข้อมูลทรัพยากร

เนื้อหาย่อ : CONTENTS Foreword Introduction PROJECTS 1. Magnetic Compass 2. Two-Pole Buzzer 3. Telegraph Key 4. Semiautomatic Telegraph Key 5. Electric Oracle 6. Powerful Electromagnet. 7. Microphone 8. Microphone Transformer. 9. Door Chime 10. Six-Volt Welding Torch 11. Electric Pencil 12. Wood-Burning Pencil 13. Electric Thermostat 14. Diving Submarine 15. Electric Thriller 16. Repulsion Coil . 17. Spinner-Type Motor 18. Two-Pole Motor 19. Magic Motor