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Is the ESI-687 a current probe or a DMM?

We need a current probe for checking out fuel injectors using a voltage-only scope. After looking at all the usual offerings on eBay, I came upon a really nifty unit, the ESI-678, which USA Tool Warehouse is offering as both a low amp current probe and a DMM for a good price (search for item # 120045454746).

However, checking on the Electronic Specialties page (

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), it IS listed in the Amp Probe section but no mention is made about the device having an output that can be connected to a scope, type of connector on the cable (BNC or banana), much less the output conversion (i.e., X mV per Amp). Granted, it does seem to be a very competent DMM, but we already have one and we need the probe function.

Wrote USA Tool Warehouse, but they only replied with the test ranges, which we already knew. Wrote ESI, got no reply.

Can anyone having one of these instruments tell me if it is really a probe or just a DMM?

Thanks,

John Courcoul

Reply to
John Courcoul
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The ESI678 has two bannana style input jacks for reading volts, ohms, etc, and the current clamp is used for inferring AC or DC amperage. These are displayed on the built-in readout. There is no output capability for this unit; it is self contained. I am confident that a set of basic leads are included if it is like any other ESI product I have seen. They really lack in marketing and customer advertising, but make up for it in product quality and cost.

Anyway, if you are looking for a current probe you may be in luck. I have a spare brand new unopened ESI695 clamp style probe that IS designed to be monitored with a DVOM or scope. The resolution on it is so fine that you can easily read it with any digital scope or GMM on the market, unlike with most high amp probes. Additionally it has a

0-80 amp range which makes it suitable to check full charging output, etc. It has two attached bannana leads for an output. You can get a bannana to BNC adapter if needed for your scope. Look here:
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I will post a link to the ESI695 below, but before I do you must know that the specs aren't totally accurate on any website that lists this unit. There is a problem with ESI having sold two different units called #695. The old unit was 0-60 amps and as far as I know is unavailable now. ESI apparently has never updated their specs on the new unit but it features 0-20 amp AC and DC ranges as well as 0-80 amp AC and DC ranges, all selected with the slide switch you will see in the picture. I use it all the time at work. I never get out my high amp probe anymore after getting this one. I have two because I got one as a christmas gift. I forgot to tell my wife that I had bought one after putting it on my "wish list" earlier last year :(

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I will sell it for

Reply to
Comboverfish

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Oh, shoot, didn't get a chance to try my bargaining skills on you ;) Got word thru other channels that the 678 was only a DMM and went ahead to purchase a 690 on eBay, where I got it for $70. This probe-only unit goes from 0-2A in 0.01 resolution and from 0-200A in 0.1 resolution, which is a very wide range. Seems it is a very new ESI offering, since it doesn't appear on their online or 2006 PDF catalog yet (check item #

120046777136 on eBay).

Should get it in a couple of days and I'll let you know how it works out.

Thanks for everything.

JMC

Reply to
John Courcoul

Cool, hope it works out for you. This thread jogged my memory that I

*have* a spare ESI695, so all is good all the way around! You will probably have difficulty if this 690 unit doesn't employ a 100 mV/amp conversion range -- it won't show useful resolution on a typical DSO with anything less IMO.

Toyota MDT in MO

Reply to
Comboverfish

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