This circuit with 117 V output was found in a 1969 Electronic Design. Drive transistors admit equivalents and information about transformers is not given.
This circuit was obtained from an old American documentation, and practically any general-purpose transistor...
This circuit is intended for monitoring an environment. It fires a relay with a sound, but only if...
This circuit is from an old documentation, but perfectly current. In place of the battery, 2 or 4...