This crystal oscillator generates a 20 MHz signal. Equivalent transistors such as BF494 and 2N2222 can be used. The stabilizing diodes can be 1N4148.
This divider by 6 is synchronized because it is implemented based on TTL or CMOS logic according to the...
Found in Popular Electronics from the 90's, this tuned to infrared modulated receiver uses a PLL....
This circuit allows you to program a resistance by combining the selected resistors. The circuit...