Variable regulator with crowbar protection (CB21189E)

This circuit was found in a Popular Electronics from the 90's. The power transistors must be equipped with a heat sink.

Non Inverting Amplifier (CB6437E)
This non-inverting AC amplifier was found on a Popular Electronics. The setting applies to any...
3 to 5 V inverter (CB9157E)
This circuit supplies 5 V from two AA batteries. The output current is 4 mA, resulting in an 11 mA...
5 V x 4A Power SUpply (CB12968E)
With this regulator we can have currents of up to 4 amps with 5V at the output. The transistor can be...