This 1 kHz TTL oscillator uses 3 inverters of a 7404 integrated circuit. The circuit is from a Popular Electronics from the 90s.
This circuit is from a 2004 documentation serving for signals from 1 MHz to 160 MHz. The antenna is...
This filter of two transistors has the cutoff frequency determined by the formulas next to the...
This Philips commercial circuit is from the 90's documentation. The integrated circuit must be...