untitled

3. Insert wires to connect the ICs, the battery pack terminal block, and
   the emitter pin of the transistors to the ground bus. Then insert a
   wire between the two ground buses to connect them, as shown in
   Figure 10-10.

Emitter

Base

Collector

Figure 10-9:

The 2N3053

transistor

pinout.

226 Part III: Let There Be Light