The charger's achievement voltage is adjustable and regulated, and has an adjustable constant-current charging ambit that makes it accessible to use with best NiCad batteries. The charger can allegation a distinct corpuscle or a cardinal of series-connected beef up to a best of 18V.
Power transistors Q1 and Q2 are affiliated as alternation regulators to ascendancy the array charger's achievement voltage and charge-current rate. An LM-317 adjustable voltage regulator food the drive arresting to the bases of ability transistor Q1 and Q2. Potensiometer R9 sets the output-voltage level. A accepted sampling resistor, R8 (a 0.1 ohm/5W unit), is affiliated amid the abrogating achievement advance and ambit ground. For anniversary amp of charging accepted that flows through R8, a 100mV achievement is developed beyond it. The voltage developed beyond R8 is fed to one ascribe of comparator U3. The added ascribe of the comparator is affiliated to capricious resistor R10.
As the charging voltage beyond the array begins to drop, the accepted through R8 decrease. Then the voltage agriculture pin 5 of U3 decreases, and the comparator achievement follows, axis Q3 aback off, which completes the signal's annular aisle to adapt the battery's charging current.
The charging accepted can be set by adjusting R10 for the adapted current. The circuit's achievement voltage is set by R9