United States
0.14 - 0.17$
price on 30.12.2022
Microphone, Speaker, Vacuum Tube, and TV Camera Tube
| Country: | United States |
| Type: | Postage stamps |
| Series: | Electronics Progress Issue |
| Nominal: | 15 ¢ |
| Year: | 1973 |
| Size: | 40 x 25 mm |
| Perforation: | line 11 |
| Mintage: | 39,000,000 |
Electronics Progress Issue
 Marconi's Spark Coil and Spark Gap 0.22$ |  Transistors and Printed Circuit Board 0.17$ |  Progress in Electronics 0.14$ |  De Forest Audions 0.14$ |