Teardown: miniature voltage tester

I've bought this miniature voltage tester in 2001 for a equivalent of $1. Similar tool is now available at dealextreme for $4.30.
It has flat screwdriver head, but it is quite fragile and I believe it would broke quickly if high torque would be applied, so you will need real screwdriver anyway.
It works in a similar way to classic neon lamp voltage indicator, but instead of single finger contact it has two, one for direct measuring and one for detecting voltage without physical contact. It is not as sensitive as battery powered indicators, finding wires in the wall is rather difficult if not impossible.

 Quite easy to open: my unit was not clued.
 The trick behind this simple tester is thick film resistor circuit.

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