Found in an Elektor from the 90s, this circuit can be powered directly by the power grid. The circuit uses a rectifying bridge that can be replaced by 4 common diodes.
Found on Popular Electronics from the 1990s, this oscillator uses a general purpose transistor. The...
This circuit was obtained from National Semiconductor documentation from the 1990s. The circuit has a...
We found this circuit in a 2005 Linear Technology manual. Observe the component values and...