2937298 | Electrical power supplies | 1960-05-17 | ||
2920260 | Battery charger and power inverter system | 1960-01-05 | ||
2813229 | Method of excitation for electroluminescent material | 1957-11-12 | ||
2694785 | Electroluminescent oscillator | 1954-11-16 | ||
1777379 | Direction signal for traffic officers | 1930-10-07 |