Logic level indicator 7400 (CB22407E)

In the figure we have a simple logic level indicator for TTL circuits or powered by 5 V.

1-Transistor MW Radio (CB18841E)
This radio version with a transistor for a crystal phone was found in a Japanese magazine from...
Infrared Alarm (CB14669E)
In this circuit of Texas Instruments an incandescent lamp is used as a light source, and lenses are...
6 or 12 V x 3 A Power Supply (CB1189E)
This source whose voltage depends only on the zener diode used, can supply currents up to about 3 A....