User manual

Figure 66: The de-soldering pump removes the solder completely from all three solder points in several

goes.

4.19 The Masterpiece

Build your own light-sensitive circuit according to the following circuit diagram. This cir-

cuit will let you practice everything you learned in this soldering course. This includes

transferring the circuit to the PCB, installing LEDs, transistor, SMD-IC and SMD diode cor-

rectly and soldering correctly. You also need to install a few wire bridges.

The circuit: The transistor ampliﬁes current for the LED light sensor. The green LED is used

as a photo element and delivers a low current. The high current ampliﬁcation of the tran-

sistor now makes a low environmental brightness sufﬁcient to switch off the LED. Using

this as a light-sensitive switch will activate the LED automatically in the evening.

If your circuit reacts as described, you passed your „master test“!