That fuse in the radio, will alert you to the simple automatic device, scheme of which was published the magazine “Radio Fernsehen Elektronik” (Germany). While a fuse F1 (see figure), the voltage between the emitter and base of transistor V1 is equal to zero and a semiconductor device is closed. Once the fuse will burn immediately on the basis of V1, a voltage is applied, opening the transistor and the led B1, included in the collector circuit will light, indicating an “accident”.
Depending on the type of led and the supply voltage select the resistor R1 so that the transistor is fully opened. If the voltage exceeds 4.5 V, in series with the led you want to include additional ballast resistor, limiting the current through Q1 to the maximum value.
Transistor V1 — any silicon, low-power: КТЗ61, КТ326, КТ208, КТ203. The diodes V2, VЗ — Д219, Д220. Led B1 — АЛ102 with any alphabetic index.
Recommend to read
THE FIRE IN THE BARREL
On a country or a plot over time, accumulate debris that owners tend to burn in the fire, that is unsafe in the fire relation. Much better for these purposes to have a special stove,...
WHY FOOT CAR
In our days people are rapidly penetrates into the remotest corners of the earth, where not only no roads, but the leg of the Explorer never set foot. Surprisingly, in its long history,...
