This is my research on setermining which ESR meter i should buy.

What is the ESR of  a Capacitor?

There is a series resistor inside capacitor, using 100kHz to remove the impedance 1/(2*pi*F*C), the impedance become small, and we can then measure the true series resistor value.

A bad E-capacitor will have larger ESR and create large ripple rather than filtering noise. Normally, a big capacitor is larger than 3 ohm.

Using this theory, we can measure the capacitor is bad/ damaged or good in condition.

Because our ESR meter only applies less than 15mV DC or peak to peak on a good capacitor, as a result we can use it as in circuit test. Because this low testing voltage, it cannot turn on the semiconductor inside a circuit under testing.

During repairing TV, LCD, Audio board, etc. we can in circuit testing the capacitor is good or not.

What is an ESR Meter for?

Firstly, what is an ESR Meter? An ESR Meter is used to measure the internal resistance of a capacitor. This feature allows you to measure a capacitor in-circuit and determine if it is faulty by its resistance. This make diagnosis consumer electronics much easier because other wise to measure a capacitor you would have to remove it from the circuit which involves desoldering, test it and then resolder it back into the circuit if not faulty. This process will have to continue for all the capacitors on the board. With an ESR Meter you can check capcacitors in moments.

How They Work

A 100KHz sine wave is pushed through the capacitor at such a low voltage that no components are triggered (opened or closed) and the sine wave is measured. From this you can determine the internal resistance of a capacitor. This outcome is determined by several variables of the capacitor:

1. Capacitance
2. Can Size (Physical Size)
3. Rated Voltage
4. Series / Model
5. Manufacturer

As a rule of thumb, if the internal resistance is above 1Ω (ohm), the capacitor is faulty. This is definately the case in most consumer electronics.

Which Meter Should I Buy ?

This was a very tricky thing to find out. There are alsorts of devices that says they measure ESR. Many are not practical, acurate or cheap. Which ones have protection, which are easy to use and so on. I have research all the main ones you will; come across and i have made a little pros and cons of each one. I also at the bottom have put my recommendation and why. This will be the one i actually bought and used.

Jingyan MESR-100 V2

Pros

• cheap
• Range 0.001R to 100R
• Auto-Ranging In Circuit
• backlit LCD display
• Uses true 100 KHz sine wave to measure the ESR value#
• is pre assembled in a durable plastic case
• can be powered from USB with a Micro USB cable
• can be powered by batteries (2 x AA)
• Test cables are connected by standard 4mm Banana Sockets
• There is a matching Capacitor Meter (Jingyan M6013 V2 Capacitor Meter), this is also very well made
• Diode protections on the inputs - they will not prevent massive voltages ie 400V, i am unsure of the maximum it would protect against
• has a basic ESR tables printed on the case

Cons

• Diode protection on the inputs - you cannot check the internal resistance of a battery.

Other ESR Meter Notes

• everyone recommends MIB Instruments for buying stuff
• how do i check/discharge a capacitor before using this meter
• what is the largest voltage it is protected against (MESR-100 V2)
• LCR meters can measure ESR and are really expensive. They should only be bought by experienced engineers or when you know why you need one.
• longer test leads can affect accuracy and need to be special sheilded
• Standard test leads are 15cm, for longer test leads need special shielding to affect the EMI inference (MESR-100 V2)
• ESR meters need to be zeroed before use
• you cannot use ESR meters on live circuits or charged capacitors
• You must make sure you discharge a capacitor before testing its ESR

Different ESR Meters

During my research i cam across the following different brands of ESR meter

• Jingyan MESR-100 V2 (there is a matching Capacitance meter aswell) i bought mine from mib_instruments on ebay
  • MESR 100 v2 - Quick look + teardown - YouTube
  • Esr Meter MESR100 v2 Hands on look at a low priced Equivalent series resistance meter. - YouTube
  • New ESR meter - MESR-100 V2 by 'Jingyan' - Page 1 - Forum thread discussing this meter
• Peak Electronics ESR70 (there is a matching Capacitance meter aswell), this is the never version of the ESR60
  • Review: Peak Atlas ESR70 Capacitance and ESR meter - YouTube
  • Peak Electronics ESR70 ESR & Capacitance Meter - YouTube
  • ESR70 & Blue ESR meters, comparison, features and differences - YouTube
• UNI-T UT612 - This is an expensive LCR meter that also does ESR.
  • T4D #70 - The last T4D for a while...UNI-T UT612 Overview - YouTube
  • Review and tear-down of UNI-T UT612 LCR meter - Page 1 - Forum thread discussing this meter
• Agilent U1733C LCR
  • EEVblog #234 - Agilent U1733C LCR Meter Teardown - YouTube
• Anatek Blue ESR meter - An older style ESR meter with no protection but is able to check a battery's ESR
• Low Cost PCB style meters on ebay (~$10 - $15)
  • Low cost ESR Meter review - YouTube - The cheap PCB style ones on eBay
  • $20 LCR ESR Transistor checker project - Page 1 - Forum thread discussing this meter

Links

Misc

• How to choose an ESR Meter - an old article on this subject but worth a read.
• Atlas ESR and ESR+ Manuals

Some Other Notes

• Some good brands of LCR: Agilent, Mastech, UNiT
• Most ESR meters do not have protection on them and a charged capacitor will kill them
• Most LCRs do not have input protection on them because it affects measurements. A charged capactitor will kill a LCR (teardown thread) (video - jump to about 32:00))
• A lot of the decent LCR have ESR meters on them, but not all
• The UNI-T UT612 LCR has an ESR option on it and can be connected to a PC for logging.
• The Agilent 1703C has some input protection on it. See eevblog video and add time here
• The MESR-100 V2 uses a true sine wave at 100KHz to test ESR and has some diodes for protection (see eevblog forum post) but this prevents it from testing battery ESRs, this is fine by me because I want to test capacitors. A good write up
• You can test a batteries ESR with a an ESR meter to check if it is knackered (see crazy guy video + time)
• You need to discharge capacitors before testing. You can check with a multimeter for voltage or with a capacitance meter with protection to see if it is charged
• You can discharge a capacitor by
  • Using a screwdriver to short the pins, only use on small capacitors
  • Using a wire and a resistor (add dads link here)
  • Use a capacitense meter with an auto discharge feature
  • Use a peak esr60/esr70 to discharge the capacitor. These will only discharge capacitors up to 50V, if you connect greater that 250v (I am guessing) it will blow the meter
  • Notes – thread 1 how to discharge and bleeder resistor notes
• The atlas peak esr60/esr70 meters, and in particular the 70, have an auto discharge feature built in with audible alerts and gets some favourablie write-ups but as with the MESR-100 you cannot check battery ESR
• LCR check impedance, Resistance and capacitance (and ESR). This functionality is probably not included on a multimeter because to measure them the devices become fragile and should only be used by professionals
• If you have a spate ESR meter it makes testing capacitors on mass easier
• The MESR V2 seems to be the best cheapest ESR meter online that works
• Those really cheap ESR (+ do other things) that are not in cases work ok and you can add your own probes onto them and then zero them.
• Another straight ESR meter id the Blue ESR meter based on a design by bob barker. I have also heard of one made by a Russian guy call GO-ESR which also has some input protection
• my Mastech MS5803 as the preferred LCR/ESR meter in my lab ? mention on eevblog forum with the mesr100 right up, see link above

Questions

• Does the honeytek really auto discharge capacitors upto 1000V