This 1967 Motorola circuit is intended for operation with signals up to 250 MHz delivering a 50 MHz signal at the output. The transistor is the MM1941, uncommon today.
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...