LED lights up on a single battery

Here we will upgrade the miniature flashlight pen. There was an incandescent light bulb. This flashlight showed a significant decrease in the brightness of the glow of the incandescent lamp when the batteries were seated. And of course, low efficiency and durability. But we will fix it.

Light-emitting diode! - Here is the solution to our problems. But changing the LED is not all. It is necessary to assemble a mini converter for the LED. There were two batteries in our lamp, so we will hide the converter in place instead of one of the batteries.

Let's look at the circuit.

The diagram shows a generator - converter. Excitation is achieved by transformer coupling.

The circuit used a KT315 transistor, a super-bright LED. We will talk about the transformer separately. For its manufacture, a ferrite ring is required - an approximate size of 10x6x3 and a permeability of about 1000 HH. The diameter of the wire is about 0.2 mm. Two coils of 20 turns each are wound on the ring. If you do not have a ring, then you can use a cylinder that is similar in volume and material. Only it is necessary to wind already 60-100 turns for each of coils. An important point: you need to wind coils in different directions. At worst, you can use a nail, but a large nail, and even turns for one coil already requires about 150. In addition, the efficiency of the nail is much lower than that of ferrite.

Let's get down to business. We disassemble the flashlight. All its parts are clearly visible.

So - we make the case for our converter.

We make a cylinder on the batteries. It can be made of paper or use a piece of any rigid tube of non-conductive material. current.

We make holes along the edges of the cylinder, wrap it with a tinned conductor, pass the ends of the wire into the holes. We fix both ends, but leave a conductor piece from one of the ends: so that the converter can be connected to the spiral.

Let's assemble the converter itself. Let's start with the transformer, I didn’t have a ferrite ring (and it wouldn’t fit into the lantern), so I used a cylinder of the same material - the cylinder was removed from the inductor from the old TV.

The first reel is carefully wound on it. The turns are fastened with glue. I climbed about 60 turns. Then the second, dangles in the opposite direction. I got it again 60 or so; I definitely didn’t count it - I could not wind it neatly. We fix the edges with glue.

We assemble the converter according to the scheme:

Everything is located as in the figure: a transistor, a capacitor, a resistor, etc. Passive and active elements are assembled, solder the spiral on the cylinder, the coil. The current in the coil windings must go in different directions! That is, if you wound all the windings in one direction, then swap the conclusions of one of them, otherwise generation will not occur.

It turned out the following:

We insert everything inside, and use the nuts as side plugs and contacts.

Solder the coil leads to one of the nuts, and VT1 emitter to the other. We glue it. You got something similar to what is shown in the previous figure.

Now you should make an LED bulb. You and I have already done this, so we will not stop.

One moment: there should be a minus of the LED on the base. Otherwise, nothing will work. There was another solution to the problem. Of course, you can create a converter module with an LED in one housing directly. In this case, as you probably already noticed, you need only two contacts.

As is clear from the figure, the converter is a "substitute" for the second battery. But unlike her, he has three points of contact: with the plus of the battery, with the plus of the LED, and the general case (through a spiral). However, its location in the battery compartment is certain: it must be in contact with the plus of the LED. Simply put, the assembly sequence in the picture cannot be changed.

Flashlight in work:

Such a flashlight is more economical and due to the lack of a second battery is light. And the main advantage! All details can be found in the landfill!

Good luck