is the well-known Blue
ESR meter from Anatek Corp in the USA.
Designed for easiest possible construction, everything is mounted on the circuit board. It's powered by a 9V battery which lasts even longer thanks to its low-current cool blue displays and low-dropout voltage regulator.
Available in kit and fully-built form, click here for all the info on the Alltronics website.
Also available from these companies (click on the name to visit their website):
John's Jukes in Vancouver, Canada (they happily ship world-wide).
Electronic Repair Guide (Jestine Yong) in Malaysia
is one of the ESR meters from EVB
in sunny Portugal (green CG
version). They're the same basic design as the Anatek Blue meter
above, and there are various versions to suit individual needs.
The black (SBX CX) version has heavy duty protection diodes in parallel with the test leads while the white (SWX) version is designed to be able to test batteries, so it doesn't have those diodes. It still has reasonable protection against charged capacitors. This new "CX" version is powered by 6x AA cells and is housed in a stronger ABS case. It also has an easy to understand chart of typical capacitor ESR figures on the front. ;-)
These meters are available fully-built from EVB in Portugal (click here) so check them out.
Click here to read a detailed impartial user review
Brief Specifications...Measurement range: 0.01 to 99 ohms, auto-ranging
Peak voltage across capacitor under test @ full scale: 50mV
Update speed: 4 readings/second
Power supply: EVB meter 6x AA cells or 9V battery (depending on model), Blue meter: 9V alkaline battery
Controls: Single push button for power on/off and zero
Dimensions: EVB: 65mm x 131mm x 30mm. Blue meter: 3.4 x 5.8 x 1.0"
Microcontroller: ZiLOG Z86E0412PSC 1866
* Test lead resistance compensation.
* Automatic power off when reading is unchanged for 3 minutes.
* Low battery voltage warning ('b' flashes on right-hand digit).
* Big, easy to read 0.5 inch (13mm) LED displays.
* Table of typical good capacitor ESRs on the front panel.
* Self-testing firmware in Blue meter kit for easier identification of construction problems.
* Kits contain all hardware and components, except batteries (prohibited in postal system).
Note: A variable DC power supply is needed to calibrate the kit meters. Click here for a little circuit you can make if you don't have one.
Overload ToleranceThese ESR meters can generally handle being connected to capacitors charged to about 50V without damage, but like most other ESR meters they will be seriously damaged by being connected to such things as the main filter capacitor charged to 300V or more, of a 240V-powered switching power supply. Some versions of the EVB meter have extra protection as noted above.