The transistor used in this circuit is uncommon today. AC124 or equivalent such as AC188K and 2N2431 can be used. The circuit is from the 80's and makes use of transformers.
This circuit is from old documentation but can be applied to modern equivalent components. The...
This circuit can keep a set of lamps on for up to 1 minute, time given by C2 and R2 that can be...
This circuit is intended to manipulate a transmitter (CW) from coded audio signals recorded on a...