Logic level indicator 7400 (CB22407E)

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

10 kHz Low Pass Filter (CB13591E)
This Salen-Key filter can use any operational amplifier and other frequencies can be obtained by...
Servo amplifier (CB23814E)
This circuit can be adapted to be used in a follow the line robot. It was found in the May 1962...
Timer 4001 (CB15512E)
The circuit in the figure uses two of the 4001's four gates to trigger a relay in a timed manner. The...