By making a mini tester, for several years I use them when repairing household electrical and radio engineering. Assembled by the classical scheme, the device allows with a sufficient accuracy for practice to measure the voltage to 300 V in DC and AC, test resistors, diodes, transistors, and capacitors.



For the manufacture of the mini-tester requires a small number of electronic components, and none of them ie rather expensive and short supply does not apply. They are always what is called a hand, you can find them in stock at any radio Amateur. And as a supporting structure, the mounting plate and the body of the instrument is used… the measuring head M42100 (or similar type) for DC voltage measurement 3 or 30 V.


Electrical schematic improvised miii-tester

Circuit diagram homemade, miii tester


Miniature socket mounted on the casing head. Here “seat” the screw MZ (it is attached to the probe “Total.”), variable resistor R2 “of the Mouth.About” lantern FRM-1, acts as a case for the power supply of the type СЦ32, СЦ21, etc. If desired, the device can add the indicator phase (the diagram shown by the dotted line) is inside the head space is enough.
After assembling glue
Scale “-30” base, takes ready. It is the binding points in the range with the upper limit “-300”. And for measuring the alternating voltage (due to the nonlinearity of the initial segment), as for measuring resistance, it is desirable to have additional scale. They are calibrated by methods that are sufficiently detailed in popular literature.
Glass in the tester, it is desirable to replace the plate of Plexiglas — will not break when knocked or dropped the device.
V. RASKOV, and t e b s K, Belarus

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