Love to collect basic and necessary household appliances. One of them is the homemade probe, which is designed not only for “continuity” of the electrical circuits in the range of 5-300 In, but also to determine the type, polarity, electric current, measure the voltage from 5 to 60 V — stand on the court readers of the respected journal. The basis of the device is a transistor analogue of the thyristor, addressed at length in “Modelis-the-designer” №1, 1999.
However, in contrast to the prior art, in ‘my design has the diode VD1, the operation indicator lamp HL1 and resistors RZ—R6. Moreover, the “shells” R6 is provided with a scale with divisions of 5, that allows acceptable error rate in the test voltage circuit.