Logic level indicator 7400 (CB22407E)

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

Logic Probe (CB10026E)
This circuit was found in old documentation but uses components that are still common. The circuit...
Voice operated transmitter (CB20412E)
This transmitter kicks in when the microphone picks up sound. This sound then modulates the signal...
Using LED on a Power Supply (CB4211E)
In the figure we have the way to connect an LED on the output of a power source to indicate the...