electronics- logic probe

LOGIC PROBE SUMMARY Logic Probe is one of the basic troubleshooting tools for common electronic logic circuits (TTL circuits). Almost all video game circuit boards are built using TTL chips. These chips will occasionally fail and the Logic Probe is a tool that affords us a look into what may be failing, and it¡¦s a very handy measuring device used to determine output logic levels. The 555 timer IC is used in this circuit. The 555 …showed first 75 words of 430 total…

…showed last 75 words of 430 total…region between HIGH and LOW. Note that the voltage range between +0.8V and +2.4V is undefined. Any steady voltage state in this undefined range should light both LED's on the logic probe & is indicative of a problem such as overloaded/ weak output or missing pull-up resistor. Many technicians do most of their troubleshooting with a logic probe; it is quick & easy. It helps find open circuits, short circuits & stuck states. It is a good start