
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
How to choose a cage for fishing
Cages various quite a lot, and can be quite difficult to choose them, what kind of tank is needed? What are the differences and so on. Therefore, you first need to understand what a...
SNOWMOBILE-“CARTOP”
Imagine readers of the venerable magazine "modelist-Konstruktor" simple in construction and small in size snowmobile, it is available for self-construction. It was designed so that there...