Constant current source (CB20484E)

This circuit uses a current regulator from the 90's. This component is uncommon nowadays. The transistor admits equivalent.

Frequency Tripler (CB4145E)
Varicap or varactor is the basic component used in this circuit of an American 80's documentation. The...
High Rise Rate Amplifier (CB20163E)
This rapid response amplifier uses an integrated one that is not common today but can be...
Load sensor (CB7900E)
Found in Popular Electronics from the 90s, this circuit powers a warning lamp when the load is...