PURPOSE: To detect and indicate charged state of a battery by detecting both voltage and current being applied onto the battery to be charged.

CONSTITUTION: When switches 8, 9 are operated simultaneously, voltage is produced across a resistor 10 and fed to a comparator (Ic) 11. When a large charging current flows, the Ic 11 produces H to turn a transistor(Tr) 12 on so as to light a LED 14 for indicating 'under charge'. When the voltage across the resistor 10 drops below a reference level, output from the Ic 11 goes to L and the Tr 12 is turned off thus turning the LED 14 off and providing H to an AND gate 19. When the voltage of a solar battery 1 is insufficient, voltage across a resistor 17 exceeds a reference level V2 and H is outputted form an Ic 18 and ANDed with the output H from the Tr 12 thus producing an output H. Consequently, the Tr 20 is turned on and a charge finish display LED 22 is lighted.