Blocking - a generator is a generator of short-term pulses repeating at fairly large intervals. One of the advantages of blocking generators is its comparative simplicity, the ability to connect a load through a transformer, high efficiency, and connect a fairly powerful load.
Blocking generators are very often used in amateur circuits. But we will run an LED from this generator.
Very often in a hike, fishing or hunting you need a flashlight. But it’s not always at hand to have a 3V battery or batteries. This circuit can start the LED at full power from an almost exhausted battery.
A bit about the scheme. Details: any transistor can be used (npn or pnp) in my KT315G circuit. The resistor needs to be selected, but more on that later. The ferrite ring is not very large. And high frequency diode with low voltage drop.
So, I cleaned up in a drawer in the table and found an old flashlight with an incandescent bulb, of course, burned out, and recently I saw a diagram of this generator.
And I decided to solder the circuit and put it in a flashlight. Well, let's get started:
To begin with, we will assemble according to this scheme.
We take a ferrite ring (I pulled out a fluorescent lamp from the ballast) And we wind 10 turns with a wire of 0.5-0.3 mm (it can be thinner, but it will not be convenient). Wound, we make a loop, well, or retraction, and we wind another 10 turns.
Now we take the KT315 transistor, an LED and our transformer. We assemble according to the scheme (see above). I put another capacitor in parallel with the diode, so it glowed brighter.
So they collected it. If the LED is off, reverse the polarity of the battery. It still doesn’t light, check that the LED and transistor are connected correctly. If everything is correct and still does not burn, then the transformer is not wound correctly. To be honest, I also started the scheme far from the first time.
Now we supplement the circuit with the rest of the details.
Putting the diode VD1 and capacitor C1, the LED will light up brighter.
The last step is the selection of the resistor. Instead of a constant resistor, set the variable to 1.5 kOhm. And we start to twist. You need to find the place where the LED shines brighter, while you need to find the place where if you increase the resistance even slightly, the LED goes out. In my case, it's 471ohm.
Well, now closer to the point)) Disassemble the flashlight
Cut a circle from the one-sided thin fiberglass to the size of the flashlight tube.
Now we go and look for details of the desired denominations of a few millimeters in size. Transistor KT315
Now mark the board and cut the foil with a clerical knife.
We fix the jambs, if any.
Now, to solder the board, we need a special sting, if not, it does not matter. We take a wire 1-1.5 mm thick. We carefully clean.
Now wrap on the existing soldering iron. The end of the wire can be sharpened and tinned.
Well, let's start soldering the details.
You can use a magnifier.
Well, it seems everyone soldered, except for the capacitor, LED and transformer. Now a test run. We attach all these details (without soldering) to the “nozzles”
Hurrah!! Happened. Now you can solder all the details without fear
I suddenly became interested, what is the output voltage, I measured
3.7V is normal for high power LEDs. The most important thing is to solder the LED))
We insert into our flashlight, when I inserted, I unsoldered the LED - it interfered.
And so, they inserted, made sure that everything climbs freely. Now we take out the board and cover the edges with varnish. So that there is no short circuit, because the case of the flashlight is a minus.
Now solder the LED back and check again.
Checked, everything works !!! Now we carefully insert all this into the flashlight and turn it on.
Such a flashlight can be started even from a discharged battery, and if there are no batteries at all (for example, in the forest on a hunt). There are many different ways to get a little voltage (insert 2 wires of different metals into the potato) and start the LED.