The use of electronics in the measurement and control of natural gas systems is now firmly established. Some subsystems are still controlled by mechanical or pneumatic means; however, the majority of control, and measurement, is by electronics. The rise of computercontrolled systems, enabling real time measurement and control, has revolutionized the natural gas industry. Central offices now have information on the entire system updated in real time. This information is invaluable in making decisions concerning system health, capacity, and safety. The responsibility of keeping this critical data flowing falls on the field personnel. An understanding of some basic principles of electronics will make troubleshooting these electronic data and control systems easier for the field technician