Logic probe, pulsar and tracer
Bookmark this page:
 Yahoo!
 Google
 Windows Live
 del.icio.us
 digg
 Netscape
|
|
||||||||||||||||||||||||||||
|
Posted by Uriah on November 28, 2006, 3:42 am
Please log in for more thread options I am looking to get a set of logic probes and need some recomendations. The only set I see with the current tracer is the old hp 547a. There is a set on ebay for $299.00 which seems high. I mainly need the tracer. Is there another Current tracer out there that might be recomended? Is the HP 545 along with the 546 pulsar and 547a tracer the best three digital probes to get or should I go with something else? I have a radio shack probe and pulsar are these any good for late model pcbs? Thank you | ||||||||||||||||||||||||||||
|
Posted by John Larkin on November 28, 2006, 11:37 am
Please log in for more thread options Logic probes aren't very useful. Get a decent oscilloscope, perferably one of the low-end Tek or HP digitals, and a good DVM. John | ||||||||||||||||||||||||||||
|
Posted by Uriah on November 28, 2006, 4:18 pm
Please log in for more thread options
What am I missing here? If you want to test a gate don't you need a logic pulsar to inject the pulse? And if you want to check for a short get don't you use the pulsar to drive the node and the tracer to see the current flow. How do you use a scope and DVM to check a stuck gate and short? I can see a scope help with floating levels but it doesn't point to the right node. A DVM can check voltage levels and shorts between pins doesn't how does it handle: Shorts, Opens within the chip and Shorts and open in the trace and Shorts and opens coming from the other gates. Thank you >
> Logic probes aren't very useful. Get a decent oscilloscope, perferably > one of the low-end Tek or HP digitals, and a good DVM. > > John | ||||||||||||||||||||||||||||
|
Posted by John Larkin on November 28, 2006, 11:56 pm
Please log in for more thread options
>What am I missing here? If you want to test a gate don't you need a
>logic pulsar to inject the pulse? Dunno, I don't often test gates in isolation. I build a circuit that's supposed to work, and if it doesn't I observe the signals with a scope and see if they make sense. If I truly want to characterize a gate by itself, I use a real pulse generator and a regular or sampling oscilloscope, depending on speed. >And if you want to check for a short
>get don't you use the pulsar to drive the node and the tracer to see >the current flow. How do you use a scope and DVM to check a stuck gate >and short? A decent DVM can measure the voltage drop in traces if a reasonable amount of short-circuit current is flowing. That's usually enough to figure out where a short is. You can also pump current into a short from a power supply, and measure trace drops. But shorts are usually solder bridges, and they're usually visible. >I can see a scope help with floating levels but it doesn't
>point to the right node. A DVM can check voltage levels and shorts >between pins doesn't how does it handle: Shorts, Opens within the chip >and Shorts and open in the trace and Shorts and opens coming from the >other gates. HP/Agilent doesn't make logic probes any more; they're not very useful in real-life logic systems. Ditto signature analyzers. Neither provides much real information. *The* fundamental instrument is the oscilloscope. Does anybody here use logic probes? John | ||||||||||||||||||||||||||||
|
Posted by on November 30, 2006, 11:35 am
Please log in for more thread options
John Larkin wrote: > *The* fundamental instrument is the oscilloscope.
A scope is big. A scope is expensive. A scope requires AC power and finding an undamaged probe. And most importantly of all, a scopre requires taking your eyes of what you are poking around in to look somewhere else. > Does anybody here use logic probes?
Unfortunately, no. Radio Shack discontinued theirs, which had much better AUDIO than the others, so these days I'm using a plain old LED most of the time. Yes, I have two scopes next to my desk, but most of the time that LED gets the job done more quikckly and simply. There are of course many things you can't do with a logic probe. But the things they could do they did better than almost everything else. Anyone else ever put a diode on the front of the RS probe to catch edges going just one way? | ||||||||||||||||||||||||||||
| Similar Threads | Posted |
| Logic probe, pulsar and tracer | November 28, 2006, 3:42 am |
| FA: Heathkit IT-12 Signal Tracer with Manual | November 13, 2004, 11:47 am |
| live wire signal tracer | August 8, 2005, 7:28 am |
| Computer controlled curve tracer | April 2, 2006, 5:52 am |
| JUD WILLIAMS TRANSISTOR CURVE TRACER MODEL A-tested/working-$25 | June 8, 2008, 8:32 am |
| probe attenuation | December 24, 2004, 1:41 am |
| radio probe | March 5, 2006, 9:27 pm |
| Amp probe questions | November 14, 2006, 6:37 pm |
| amp probe question | February 7, 2008, 6:01 pm |
| UK - where can I buy an appropriate temperature probe? | February 13, 2008, 6:55 am |
| Recommendations for a TEK 465b probe | January 12, 2006, 5:21 pm |
| Oscope measurement and probe grounding | August 28, 2005, 11:20 pm |
| Type K Thermocouple probe question | September 24, 2008, 9:18 am |
| Type K Thermocouple probe question | September 24, 2008, 10:04 am |
| where to find multimeter probe for connecting to male DB connectors? | August 29, 2006, 3:36 pm |
>recomendations. The only set I see with the current tracer is the old
>hp 547a. There is a set on ebay for $299.00 which seems high. I
>mainly need the tracer. Is there another Current tracer out there that
>might be recomended? Is the HP 545 along with the 546 pulsar and 547a
>tracer the best three digital probes to get or should I go with
>something else? I have a radio shack probe and pulsar are these any
>good for late model pcbs?
>Thank you