This circuit was originally designed for the practice of Morse code, something common in 1966, the year of the publication in which I found it. The circuit uses a valve transformer for valve equipment and is powered by a 110 V or 220 V network. The diode can be 1N4004 or 1N4007 depending on the network. The neon lamp is common as the NE-2H or equivalent.
| Clique na imagem para ampliar |
