JL Sargent Posted March 2, 2010 Share Posted March 2, 2010 This LH2821B meter is available from several sellers on Ebay. Some of these sellers claim it can do ESR (equivalent circuit resistance) also which is of interest to me. That feature on this meter not nearly as obvious as other meters like BECs BK 885 meter. What do you guys think of this meter and how does it do ESR, a measurement I'm new to? The Ebay ad has a PDF link to the manual also. I notice it has a Parallel/Series button which may be the ESR function? Seems like a good bang for the buck if it does everything. http://cgi.ebay.com/Handheld-bridge-LCR-Meter-0-3-ac-0-01-resolu-TH2821B_W0QQitemZ220413136240QQcmdZViewItemQQptZBI_Electrical_Equipment_Tools?hash=item3351a58d70This item number is 220413136240 Quote Link to comment Share on other sites More sharing options...
Marvel Posted March 2, 2010 Share Posted March 2, 2010 ESR (Equivalent Series Resistance) is not the same as Equivalent Circuit Resistance... Quote Link to comment Share on other sites More sharing options...
djk Posted March 3, 2010 Share Posted March 3, 2010 The dissipation and Q functions will sort out bad components,which is why you pay more for this kind of meter. If a component has poor ESR it will have poor dissipation or Q. Close enough. Consider having it shipped directly to BEC for evaluation. If he thinks it's junk you can return it within 14 days. Quote Link to comment Share on other sites More sharing options...
JL Sargent Posted March 3, 2010 Author Share Posted March 3, 2010 OK, thanks guys. Study on Q and dissipation next. Quote Link to comment Share on other sites More sharing options...
BEC Posted March 3, 2010 Share Posted March 3, 2010 The dissipation and Q functions will sort out bad components,which is why you pay more for this kind of meter. If a component has poor ESR it will have poor dissipation or Q. Close enough. Consider having it shipped directly to BEC for evaluation. If he thinks it's junk you can return it within 14 days. I like that idea. I can compare it to one I know is good. I would buy one myself if that cheap meter is any good. Bob Crites Quote Link to comment Share on other sites More sharing options...
JL Sargent Posted March 3, 2010 Author Share Posted March 3, 2010 Here is a link to the company's website. They make all kinds of test equipment. I don't doubt its a good meter. I would suggest buying from a state side seller though, to insure getting the proper 110v transformer. http://www.tonghui.com.cn/eng/ShowProInfo.asp?Product_id=106 Also found this good read in case others are interested: In physics, the dissipation factor (DF) is a measure of loss-rate of power of a mode of oscillation (mechanical, electrical, or electromechanical) in a dissipative system. It is the reciprocal of Quality factor, which represents the quality of oscillation. For example, electric power is dissipated in all dielectric materials, usually in the form of heat. In a capacitor made of a dielectric placed between conductors, the typical lumped element model includes a lossless ideal capacitor in series with a resistor termed the equivalent series resistance (ESR) as shown below.[1]The ESR represents losses in the capacitor. In a good capacitor the ESRis very small, and in a poor capacitor the ESR is large. Note that theESR is not simply the resistance that would be measured across a capacitor by an ohmmeter.The ESR is a derived quantity with physical origins in both thedielectric's conduction electrons and dipole relaxation phenomena. In adielectric only one of either the conduction electrons or the dipolerelaxation typically dominates loss.[2] For the case of the conduction electrons being the dominant loss, then , where σ is the dielectric's bulk conductivity, ω is the angular frequency of the AC current i, ε is the lossless permittivity of the dielectric, and C is the lossless capacitance. A real capacitor has a lumped element modelof a lossless ideal capacitor in series with an equivalent seriesresistance (ESR). The loss tangent is defined by the angle between thecapacitor's impedance vector and the negative reactive axis. If the capacitor is used in an AC circuit, the dissipation factor due to the non-ideal capacitor is expressed as the ratio of the resistive power loss in the ESR to the reactive power oscillating in the capacitor, or . When representing the electrical circuit parameters as vectors in a complex plane, known as phasors, a capacitor's dissipation factor is equal to the tangentof the angle between the capacitor's impedance vector and the negativereactive axis, as shown in the diagram to the right. This gives rise tothe parameter known as the loss tangent δ where . Since the DF in a good capacitor is usually small, δ ~ DF, and DF is often expressed as a percentage. DF approximates to the power factor when ESR is far less than Xc, which is usually the case. DF will vary depending on the dielectric material and the frequency of the electrical signals. In low dielectric constant (low-k), temperature compensating ceramics, DF of 0.1% to 0.2% is typical. In high dielectric constant ceramics, DF can be 1% to 2%. However, lower DF is usually an indication of quality capacitors when comparing similar dielectric material. References ^ http://www.cartage.org.lb/en/themes/sciences/physics/electromagnetism/electrostatics/Capacitors/Applications/BasicConsiderations/BasicConsiderations.htm ^ S. Ramo, J.R. Whinnery, and T. Van Duzer, Fields and Waves in Communication Electronics, 3rd ed., (John Wiley and Sons, New York, 1994). ISBN 0-471-58551-3 Quote Link to comment Share on other sites More sharing options...
JL Sargent Posted March 3, 2010 Author Share Posted March 3, 2010 I found this to be the best state side deal on this meter ($151.99 delivered) if anybody else is interested. I haven't bought one yet but considering it. http://cgi.ebay.com/Handheld-bridge-LCR-Meter-0-3-accuracy-0-1-resolu_W0QQitemZ300313817293QQcmdZViewItemQQptZBI_Electrical_Equipment_Tools?hash=item45ec1930cd Quote Link to comment Share on other sites More sharing options...
JL Sargent Posted March 3, 2010 Author Share Posted March 3, 2010 ESR (Equivalent Series Resistance) is not the same as Equivalent Circuit Resistance... What's the difference? When talking about capacitors as we are, seems the cap is a circuit of sorts. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.