User manual

24
6. Charging Rechargeable Batteries with the USB
Source
USB is a standard in the computer area and widely distributed. Electronic devices,
computer accessories, such as external hard discs, but also small lamps, fans, etc.
can be operated with it.
Most mobile phone providers now offer micro USB as the standard device socket
for the charging contact.
The USB standard in the computer is set up so that the devices will rst start in
Low Power-Mode (100 mA or 150 mA) and request a higher current before they
switch to regular mode.
The different applications mean that mains units with a 5-V-USB current source are
very common. The current supplied by the mains unit is usually at 500 to
2,000 mA. This kind of USB mains unit is well suitable for the other charging
experiments.
Fig. 021: USB mains unit