DMM freq counter vs standalone counter - Page 1
Forum section: electronics / beginners

author: SnakeBite
author_rank: Regular Contributor
timestamp: November 10, 2013, 11:33:16 am
content: Hi,i want to know the differences between the two , adventage and disadvantage etc..i have FLUKE 87V and EXTECH MM570 and they both have built-in counter till 200KHZ (which is enough for my uses)thanksIdo

author: dfmischler
author_rank: Frequent Contributor
timestamp: November 10, 2013, 12:14:31 pm
content: DMM counters are lower cost and take less space but usually only measure frequency and duty cycle. Standalone counters measure higher frequencies (perhaps 100 MHz, or even multiple GHz), and may also offer measurements of period, ratio and/or interval between two signals, raw counting of signal transitions, etc. and often allow use of an external frequency reference, and so on. But they cost more and take up bench space and a power outlet and generally have a BNC input instead of convenient test leads.I have anHP 5315Bthat I use infrequently, but when it is the right tool for the job it is awesome to have.

author: cyr
author_rank: Frequent Contributor
timestamp: November 10, 2013, 12:35:59 pm
content: No different than most other dedicated instruments vs. built-in functions:Pro:* More accurate (few ppm or better)* Higher resolution (8-10 digits)* Larger range (MHz or GHz vs kHz)* Usually more functions like statistics, computer control.Con:* More expensive* Takes up bench space / not portable

author: dr.diesel
author_rank: Super Contributor
timestamp: November 10, 2013, 01:04:46 pm
content: How accurate do you require? eBay is full of old school counters that can easily be modded with OCXOs for much higher accuracy.My first counter was a Ramsey CT-90, bought it for $50 shipped, I modded it with a TCXO. It holds (once calibrated/trimmed) within about 1hz against my GPSDOed HP 53132A.

author: FaultlineAudio
author_rank: Unknown
timestamp: November 10, 2013, 04:31:25 pm
content: Having a stand alone counter is often more convenient because your not tiring up a DMM for a frequency reading. I have several Fluke 1900A counters. If you watch eBay you can often buy them for under $20.00

author: dr.diesel
author_rank: Super Contributor
timestamp: November 10, 2013, 04:33:43 pm
content: 8-Digit counter for $39 buy it now:http://www.ebay.com/itm/FLUKE-FREQUENCY-COUNTER-7720A-Chanel-A-works-Chanel-B-NOT-WORKING-/221312861817?pt=LH_DefaultDomain_0&hash=item3387464679

author: olsenn
author_rank: Frequent Contributor
timestamp: November 10, 2013, 04:45:20 pm
content: Two three biggest factors I imagine most people are interested in, are:1. Frequency Range - Modern benchtop counters typically have two inputs; a high-impedance, low-frequency (<100MHz) input using a BNC connector, and a high-frequency, low-impedance (50-ohm) N-connector. Periods as high as hours, to frequencies as high as gigahertz can be measured.2. Timebase Stability - A good counter will offer a build in TCO or TCXO crystal as well as the option to use an external reference (which could be an atomic clock).3. Precision - This is only as good as the timebase stability, but decent counters offer 8+ digits of resolution on their display. Your Flike-87 will only give you 3 or 4 digits to play with.

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: November 10, 2013, 09:55:29 pm
content: I went with the BK 1823A 2.4GHz Frequency Counter. Benifits, 9 digit resolution, 1ppm, heat stabilized 10MHz crystal, .1Hz to 2.4GHz, 3 channels. Yes, they are bigger and take us bench space, more expensive but the accuracy and other functions make them very useful. The DMM counters are great for basic readings but if you are serious about looking at your frequency with high resolution then a good bench counter can't be beat!

author: Rasz
author_rank: Super Contributor
timestamp: November 10, 2013, 10:04:57 pm
content: Quote from: dr.diesel on November 10, 2013, 04:33:43 pmShipping:$342.13ahahahahahah

author: Nerull
author_rank: Frequent Contributor
timestamp: November 10, 2013, 10:12:10 pm
content: To where? It's $15 here which is a bit much for one state away but not excessive by ebay standards.

author: deth502
author_rank: Frequent Contributor
timestamp: November 11, 2013, 01:03:53 am
content: Quote from: Rasz on November 10, 2013, 10:04:57 pm$21.57 for me