Maker Factory ELECTRONICS EXPERIMENTS BOX Manual page 252

Circuit 30: T1 blocks, if the solar cell is not supplying power due to darkness. R2 triggers T2 to switch
through and LED1 turns on. However, T1 becomes conductive in a bright environment and the solar cell sup-
plies electricity. The T2 base current is discontinued, T2 blocks and LED1 turns off.
254
Fig. 3.29: Circuit
29: Simple bicycle
light
Fig. 3.30: Circuit
30: Automatic
bicycle light with
solar cell