This circuit was found in a Popular Electronics from the 90's. The CMOS integrated circuit used is not very common nowadays. The range depends on the infrared LEDs. R7 can be changed.
Found in old American documentation, this filter has a 8 dB per octave attenuation. The formulas for...
This circuit is intended for detecting 3 levels power grid voltage, and it can be adapted to...
This circuit allows the use of two triggers (inverters or NAND gates connected in this way) to...