Hi,
This ESR meter has been mentioned in the forum a couple of times, but I have not seen a teardown of it yet, so here goes...
It is another basic ESR meter, available on eBay and some other sites for around $59.00. It is powered by a 9 volt battery, which was included (a powerful cell, yeah!) together with some basic test leads.
Current draw when switched on is about 17mA (backlight on), double that when actually measuring.
It has 3 manual ranges (0-1R, 0-10R and 0-100R) and one auto range. I have yet to find out why I would use a manual range, the auto range is fast enough (<2s).
It looks like the design idea was to solder the banana jacks directly on the PCB, probably for another type of case. It just doesn't work with this one, so they just soldered wires.
It's a basic design with a PIC16F886, a LMV824 op-amp and support circuitry
On the bottom of the PCB there is just a LM340 and a 20cm wire to bridge a 1/10" jumper... Don't ask.
(Yes, I removed the wire. At first I thought is was resistance wire, so I measured it but it came out at 0.02 ohms. Since the accuracy is still ok who knows...)
Accuracy seems ok, a 100R 1% resistor:
And a 0.15R 5% one:
And of course the (very obvious bad) 1000u/16V cap:
It measures using a 100KHz square wave with an amplitude of about 400mV. I've been using it a few times and it picks out the bad caps ok, also in circuit.