Discover pinout battery "Krona".At most the battery or the battery of this type, as well as at an equivalent power supply unit, a large terminal - negative, low - positive.In the charger, and from any device powered by a "crown", the opposite is true: a small terminal - negative, big - positive.
Make sure that battery, which is available in your presence, indeed the battery.
Determine the charging current of the battery.For this purpose its capacity expressed in milliamp hours, divide by 10. Upon receiving the charging current in milliamperes.For example, the battery capacity of 125 mAh Charging current is 12.5 mA.
as a power source for the charger, use any power supply, the output voltage of approximately 15V, and maximum current consumption does not exceed the
charging current of the battery.
Discover pinout stabilizer LM317T.If you put it face marked to him, and displayed at the bottom, the left will be regulating the conclusion, in the middle of the output on the right - the entrance.Install the heat sink on the chip, which is isolated from any other conductive parts of the charger, because it is electrically connected to the output of the stabilizer.
IC LM317T is a voltage stabilizer.To use it for other purposes - as a current regulator - between its output and adjusting the output enable pull-up resistor.His resistance is calculated according to Ohm's law, given that the output voltage of the stabilizer is 1.25 V. To this end, the charging current, expressed in milliampere, substitute in the following formula:
R = 1,25 / I
Resistance succeed in kiloomah.For example, the charging current of 12.5 mA in the calculation would be as follows:
I = 12,5 mA = 0,0125A

R = 1,25 / 0,0125 = 100 ohms
Power resistor in watts calculated by multiplying the voltage drop across it equal to 1.25 V, on the charging current, and pre-translated in amps.Round the result up to the nearest value from the standard range.
Connect Plus power supply to the positive battery, battery to the negative input of the stabilizer, the stabilizer control output to negative power supply.Between input and output adjustment of the stabilizer include electrolytic capacitor 100 uF, 25 V plus to the entrance.Ceramic shunt him any capacity.
Turn on the power supply and allow the battery to charge for 15 hours.