discussed in the following post; the circuit can be modified in many different
ways as per individual requirements and applications.
main section of the circuit.
after the other in response to a rising potential fed at its pin#5.
level at the "signal input" pin out of the IC.
battery voltage which needs to be charged.
charge level of the battery by illuminating in sequence, and finally when the
last LED is lit which happens when the battery gets fully charged, the SCR is
triggered shutting off the charging process permanently until the power is
IC, the preset associated with IC is set as per the required full charge limit
of the connected battery.
for controlling the IC dissipation.
in the array which may be selected for the full charge indication is not
BC557 is also switched ON triggering the SCR. The SCR instantly grounds ADJ pin
of the LM338 completely disabling the IC and the output to the battery.
inhibited from getting over charged.
18V, 21V and 24V batteries, in fact any voltage that may lie between 1 and 24V.
this battery would be 7V.
from the BC557 network.
LM338, may be a 9V or a 12V input.
terminal points receive a 7V output.
LED just flickers ON at this voltage, meaning at the applied 7V.
During the charging process each LED will correspond to 7/10 = 0.7
volts, meaning say at 5V the 7th LEd will be illuminated and with a rise of
0.7V the subsequent LED will be lit and the sequence will proceed from 7t to
8th to 9th and then finally to the 10th LEd shutting off the circuit and the
charging of the battery.
If the above circuit fails to respond with an SCR, the following circuit using a transistor latch can be employed: