As I mentioned in my recent columns on the topic of adding pull-up or pull-down resistors to the inputs of unused or partially used logic gates and functions (see Part 1, Part 2, and Part 3), I was ...

When testing circuits with a logic probe, it is sometimes difficult to watch the LEDS on the probe to determine the logic state. With this probe the logic states are audible. This probe is designed ...

The logic probe is powered from the device under test (DUT)—it may be any binary logic, which can be powered in the range +2 V to +6 V. This may be a microcontroller or 74/54 series logic chips, ...

Logic probes are simple but handy tools that can be had for a couple of bucks. They may not be the sexiest pieces of test gear, nor the most versatile, but they have their place, and building your own ...

Fig 1. A typical CMOS input circuit comprises a “P” and “N” transistor. One is fully “on” for logic high, and the other is “on” for a logic low. Fig 2. When a CMOS input pin is at logic high or low ...