Logic Probe

[johnnydiaz]

Who uses a logic probe and finds it helpful during the troubleshooting process?

[Kiriakos GR]

Re: Logic Probe

I will mention just one application, and this is about PLC programming (industrial automation).
Logic analysis is about commands send over serial or parallel communication ports.
And it could expand even to communication protocols used in mobile phones.

The mixed mode scopes (MSO) is basically an DSO with the additional circuitry and software, for logic analysis.

The bandwidth of the MSO in MHz or GHz is very important.
Its like an FM radio receiver, you have to tune it first in the right frequency, and then the inner Stereo decoder will give you Stereo sound.

[japlytic]

Re: Logic Probe

I find a logic probe useful to identify the state on a digital pin and only use one hand with the other hand being used for something else important.
Mine also detects the difficult to detect high impedance state (Tri-state in National Semiconductor terminology) and has a pulse memory.

[Longbow]

Re: Logic Probe

A simple logic probe will indicate a high or low state, or will flash if the state is changing. Don't confuse this small tool with a logic analyzer. The handheld probe was popular in the 60's and 70's when everything was made with TTL discreet logic and entire pc boards loaded with TTL chips were common. These days you might find a few discreet gates here and there, but it is usually faster to use your dvm since you already have the probes in your hands.