The proposed indicator allows you to capture voltage of 6 — 12V (i.e., below the ignition of the neon lamp) and above. In contrast to the known similar kind of indicators, there are no buttons and limit switches measured values, which a wrong selection can lead to distortion of information, and even to failure of the device.
When checking phase voltage 220V in addition to led lights, knopka HL3 HL1, but when checking the line voltage in the 380 V is also neonka HL2. To check the circuit indicator is connected by means of electrodes ХР1 and XP2.
Search for “phase” is simultaneously touching electrode-sensor E1 and the target point electrode ХР1. When “phase” was found — lit neonka HL1. The diode VD1 is in this case, the decoupling circuit neonek from the led. So, when operating in AC power, the led glows from the positive half sine wave voltage, and HL1, HL2 — negative. Working in DC networks, the indicator allows you to set the polarity (for example, rectifiers).
Using a dial indicator, you can determine the serviceability of the p-n structure of the semiconductor (specifically the diode). It is necessary to connect one of the electrodes to pole DC voltage source and the other through the diode to the other pole. The led should only light with one polarity. If the glow will be in both, then the diode is shorted; if the same light is not — the diode is cut.
Except specified on the circuit nenok can be used by neonki from starters of fluorescent lamps. Dismantling the starter, select neonka with light, nezakonnym glass. The quality of the led used АЛ307Б. Diode — КЦ106Д, resistors — MLT
The indicator performed in the form of two holders. One of them is the resistor R3, and the outside electrode-sensor E1 in the form of a ring of copper foil (wire) In the other holder placed the rest of the scheme. This holder is preferably made of a transparent material, so that even the peripheral vision to see the glow of neodoc and led. Of course, a connection cable holders must have double insulation
S. LEVCHENKO, St. Petersburg