This circuit is one of many that the reader can find in this section for testing crystals. The circuit uses an indicator LED. Transistor Q1 determines the maximum crystal frequency that can be tested.
This circuit from the 40's is a conventional analog multimeter with several scales. Its accuracy will...
The integrated circuit used in this project is no longer very common, but if found it can result in...
This switched regulator configuration was found in Motorola's 1969 documentation. The integrated...