Instead of multimeters series "M" or "M" multimeters have tiny "DT-182". Source power in these multimeters is battery type AA 12 V. However, as practice shows radio, the use of these batteries not more than a few weeks, but if the multimeter immediately after measurements off, then even less.
The way out of this situation. It consists in using a voltage Converter from one lithium battery voltage of 2.7 4.2 In…to get 12 with a current up to 300 mA. Scheme Converter (Fig.1) made on the chip LT1308B and Linear Technology has only a few components. The main elements are the inductance L1 and diode VD1.
The second option power multimeter "DT-182" may the Converter (Fig.2), which serve as a source of three AG13 battery type or L1131.
The output of the power supply unit have 12 V at currents up to 500 mA. Need just to make it so that the batteries could regularly recharged, the batteries placed in the battery compartment of the multimeter. and in the case enough space to install a small fee the Converter. Firm Linear Technology offers your drawing Board (Fig.3), but I made it in hinged manner on breadboard Board.
When installed in the housing multimeter the Converter is isolated from the main Board with a strip of packing tape (Scotch tape).
Test power supply with batteries in the multimeter DT-182 showed that during the half a year it worked properly (even at a voltage of 1.0 V on each battery).
Author: P. Bobonich, Uzhgorod, Ukraine