This organ, played by a probe was found in no old documentation, but it can be easily implemented these days. The integrated circuits are 555. The trimpot allows individual tuning of the keys.
This simple charger was found in a 1980s documentation. The transistor may be the TIP42 with a...
This circuit is used to run light bulbs around street signs. Incandescent lamps up to 40 W are...
This high frequency or RF amplifier was found in a 90s Popular Electronics. The circuit can be...