Integrator with JFET (CB6229E)

This circuit was found in an 80s National Semiconductor documentation. The configuration holds true for modern JFETs.

Magnetic Field Tracer (CB22346E)
This circuit uses a Hall device from that time as a sensor. The circuit is from an English...
Alternating tone siren 555 (CB9202E)
Found in Radio Electronics from the 90s, this siren finds many variations on this site. The...
Sinusoidal and Rectangular Oscillator (CB19259E)
This audio generator that produces both rectangular and sinusoidal signals was found in a...