Two LEDs with different color (e.g., red and green), you can build a simple indicator for voltages from 4.5 to 220 V. It is also able to determine the polarity of the source in the range 8-220 V. When measuring AC voltage, both diode glow, but if it is constant — lights one of them depending on the wiring polarity indicator. The scheme proposed by the Czechoslovak journal “Amaterske Radio”.
Measure the mains voltage from 110 to 220 In a short-term need. a current-limiting resistor R1 (see Fig.). In addition to the household, the indicator is used and motorists.
Czech 1NZ70 Zener can be replaced with a tense domestic stabilization 5-6 In, for example Д815А, the diodes V1 and V5 — any low-power silicon, for example D226. LEDs can be АЛ102Б (red) and AL 102V (green).
Recommend to read
THE FIRST ARMORED WHITE
Daimler and Benz invented his machines in the nineteenth century, but reliable and widespread means of transport the vehicle was only in the XX-om. Military immediately expressed...
WOODEN GRASSHOPPER
Recumbent I've collected over the ten days together with their children and we called him "Grasshopper". Rear wheels have "Grasshopper" — from Bicycle "the Schoolboy one of which is...
