RadioKot писал(а):
а я и сам не понял к чему мне были сказаны эти ваши слова???
Странно... сказано же что конденсаторы - это защита от импульсов, что способна генерировать микросхема, выбросы напряжения могут губительно сказаться на зарядке аккумулятора и даже привести к его взрыву! Ведь недаром в даташите на LM317T пишут что конденсаторы надо установить.
EXTERNAL CAPACITORS
An input bypass capacitor is recommended. A 0.1μF disc or
1μF solid tantalum on the input is suitable input bypassing
for almost all applications. The device is more sensitive to
the absence of input bypassing when adjustment or output
capacitors are used but the above values will eliminate the
possibility of problems.
The adjustment terminal can be bypassed to ground on the
LM117 to improve ripple rejection. This bypass capacitor
prevents ripple from being amplified as the output voltage is
increased. With a 10μF bypass capacitor 80dB ripple rejection
is obtainable at any output level. Increases over 10μF do
not appreciably improve the ripple rejection at frequencies
above 120Hz. If the bypass capacitor is used, it is sometimes
necessary to include protection diodes to prevent the
capacitor from discharging through internal low current paths
and damaging the device.
In general, the best type of capacitors to use is solid tantalum.
Solid tantalum capacitors have low impedance even at
high frequencies. Depending upon capacitor construction, it
takes about 25μF in aluminum electrolytic to equal 1μF solid
tantalum at high frequencies. Ceramic capacitors are also
good at high frequencies; but some types have a large
decrease in capacitance at frequencies around 0.5MHz. For
this reason, 0.01μF disc may seem to work better than a
0.1μF disc as a bypass.
Although the LM117 is stable with no output capacitors, like
any feedback circuit, certain values of external capacitance
can cause excessive ringing. This occurs with values between
500 pF and 5000 pF. A 1μF solid tantalum (or 25μF
aluminum electrolytic) on the output swamps this effect and
insures stability. Any increase of the load capacitance larger
than 10μF will merely improve the loop stability and output
impedance.
http://www.datasheetcatalog.org/datashe ... wladfy.pdf