I was given a logic probe. I have not used one before. I am wondering where it will be useful to me. It can be set to TTL or CMOS. I do not know the difference except that I think TTL are the 5 volt logic ICs like 74xxx. What are some common things I can test with this probe so that I can get a feel for it?
If you don't yet understand the difference between TTL and CMOS then a logic probe will be of limited use. Do some reading. TTL is now obsolete but you will still find it in old gear. Old CMOS can be static sensitive so easy to kill chips by probing. Use static precautions.
When I worked on logic boards, I used one all the time. For anything else, it looks pretty in the drawer. It detects logic levels, rather than voltages per se. IN TTL with its 5v power supply, a logic high could be 3v or it could be 4.9v, either one is a valid logic high, and the probe will not differentiate. When you want to know if a logic signal is functioning, that is all you need to know. Kinda like looking at a toggle switch - it is either on or off, and doesn;t matter how hard you threw the lever.
The logic probe is a great tool, but only useful for looking at logic signals. One cool aspect was they could pick up tiny little narrow spikes that were - back when - VERY hard to see on a scope.
The logic probe is a great tool, but only useful for looking at logic signals. One cool aspect was they could pick up tiny little narrow spikes that were - back when - VERY hard to see on a scope.
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