Before I worked with computers, I was interested in electronic circuits and the construction of all kinds of electronic devices. Over the past few years I’ve rediscovered this interest and occasionally explore both old and new hardware.
Velleman K8055N – interface board for USB
LED display DL-2614, HDLO-2614
Assignment of the pins of the ATmega 328P in the Arduino Uno
Other sources
List of 4000-series integrated circuits (Wikipedia)
List of 7400-series integrated circuits (Wikipedia)
LOGIC Pocket Data Book (Rev. B, 7400 series Texas Instruments)