Of course, such a decision will deprive the screwdriver of its main advantage. mobility. But this is a fairly popular option among homemade ones, if you can’t get a set of batteries to replace the old ones.
The power supply is very cheap and simple. It is built on the basis of a powered electronic transformer. Any electronic transformer with a power of 50 to 100 watts can act as a test subject. There is no more sense, since the power will still increase. details on this issue can be found in the article on increasing the power of the transformer.
The ATX format power transformer was taken from a computer PSU.
Native windings were dismantled and new ones were wound in their place. For those who will use similar cores, the primary winding contains 55 turns, and the winding was carried out by a three-core wire (0.5 mm each core). The winding did not fit into one layer, so each layer was carefully insulated.
Video: Screwdriver Battery Conversion Kit
Secondary winding with the calculation: for 1 turn. 2 V. The recommended wire diameter is 4 mm. For the convenience of winding, you can use a harness made of thinner wires.
The split core can be glued with superglue or with adhesive tape.
The power supply is of an unstabilized type, so the output voltage will deviate slightly from the calculated one. But there will be nothing wrong.
KD2997 diodes are installed as a diode rectifier. They are at 30 A and can work without problems at frequencies up to 100 kHz.
In the images, the diode bridge is made on a separate board, although the circuit board for download contains this rectifier.
Diodes must be installed on the heat sink and isolated from the radiator using mica gaskets.
Power transistors of the power supply are also attached to the radiator. They are from the MJE line, or rather, the MJE13009. But you can replace it with 13007 in the TO220 case, although the seats on the board are provided for keys in the TO247 case.
The resulting device was installed in the housing from the battery. At the end, a network cable was connected.
So, the resulting version of the power supply is the simplest and has the right to exist as one of many. Naturally, you can construct something more serious, but this will complicate the design.
Attached files: DOWNLOAD.
AUTHOR: AKA KASYAN