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Article #15106Basic bench equipment query
From: David Covell
Date: Tue, 15 Dec 1992 17:04
Date: Tue, 15 Dec 1992 17:04
40 lines
3025 bytes
3025 bytes
I'm preparing to outfit myself with a basic bench setup, ie scope, function generator, power supply, DMM, and transistor tester (lots of in-circuit go/no go testing). As always when I begin to shop for things I start with low expectations... basic, inexpensive, etc. But, as I read descriptions of the functions and specs of various options I become convinced that I just can't live without the extra features available only on the higher- priced items, like cursors and auto-setup on the scope, touch-hold and min/max on the DMM, etc. This is a pattern I've developed over the years when contemplating purchases of techniacl items, and I frequently realize I didn't need the extra features after all, or they don't work the way i expected. Of course, by then it's too late... In an attempt to avoid doing that this time I'd appreciate some feedback from this group on what's really appropriate for the average home hobbyist. My primary need is for troubleshooting and tweaking audio equipment, both tube and transistor. I occasionally need to work with digital circuits but rarely above 20Mhz. The scope is the biggest decision and the one that could save me the most money. My options range from a basic 20Mhz Elenco at $400 to a Tektronics TAS series 60Mhz with auto-setup, cursors, known quality, etc at $1550. Both Tek and Fluke claim you should go for a bandwaidth of 5X the fastest signal you plan to read; just how true is that? I'm sure that if you need to measure critical rise times, capture glitches, etc that's probably true, but my needs are less strict. What's a more reasonable factor than 5X for applications where accuracy is less critical? Can I use a 20Mhz scope on waveforms that approach 20Mhz and get reasonable accuracy and visibilty? I definitely need dual trace, but how much do I need dual time base? Delay? Are Elenco, Hitachi and B+K Precision scopes in the <$1000 range reliable? If not, I'd definitely go with thr Tektronics. Tek has eliminated several lower-end scopes and the choices now are limited to the 20Mhz single-trace 2205 at $700 or the 60Mhz TAS455 for $1550. That's a hard choice, and I'm surprised there's no middle ground. DMM's another hard choice; The Fluke 79 has most of the features I want (in fact maybe more than I need). I'd prefer something cheaper than it ($185) but it has a high range for capacitance (to 9999uF) and the Touch-hold feature, which will be handy in freeing me from trying to look at the meter while probing a 480V tube plate. As always, I'd prefer to find some good used deals, but the only things I see are old and feature-poor. Any advice? Pointers?
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arc1-ca.pugleaf.net!sparky!uunet!olivea!spool.mu.edu!uwm.edu!zaphod.mps.ohio-state.edu!cs.utexas.edu!asuvax!chnews!hfglobe!dcovellShow Full Headers
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Path: arc1-ca.pugleaf.net!sparky!uunet!olivea!spool.mu.edu!uwm.edu!zaphod.mps.ohio-state.edu!cs.utexas.edu!asuvax!chnews!hfglobe!dcovell From: dcovell@hfglobe.intel.com (David Covell) Newsgroups: sci.electronics Subject: Basic bench equipment query Message-ID: <BzB8rD.BDp@hfglobe.intel.com> Date: 15 Dec 92 17:04:22 GMT Organization: Intel Corporation Lines: 40