Found in an Electronic Design, this circuit makes use of general-purpose bipolar transistors. The circuit can be adapted to operate at lower voltages
This circuit was published in a January 1971 issue of Radio Electronics to check television...
Found in Popular Electronics from the 90's, this tuned to infrared modulated receiver uses a PLL....
This 1967 General Electric circuit makes use of an array of 3 (integrated) transistors for an...