This circuit was found in an Elektor from the 90s. It makes use of digital CMOS integrated devices common today. The signal is controlled automatically sequentially.
This new AMS device consists of a digital color sensor and proximity sensor that also incorporates an infrared...
This amplifier produces a few hundred milliwatts of Input 100 pF audio over a load of 4 or 8 ohms...
This transmitter for modulated infrared remote control was found in documentation from the 90s....