User manual

Fig. 067: Circuit diagram for the solar night light

Once it grows dark (e.g. with the solar module covered), the LED will light up. It

goes out once the solar module is exposed to light again.

The current from the lit solar modules blocks the T1 collector-emitter section via

its basis. The rechargeable battery is charged via the diode D1. If no light hits the

solar module anymore, the basis current stops and the collector-emitter section

routes the current from the rechargeable battery via the LED. The LED lights up.

A lithium rechargeable battery no longer suitable for mobile phones can still be

sensibly used in this manner. In practical use, the rechargeable battery is charged

during the day and will emit energy again in darkness - in the experiment setup

here through an orange light-emitting diode. Depending on rechargeable battery

capacity and charge duration, the LED may be lit all night. E.g. candle LEDs in a

self-made lantern are ideal for operation. The lantern casing can easily be made,

e.g. from an empty tetra pack.