Figure 1.7. This figure is very similar to Figure 1.5. On the left is a battery labeled E1. Its negative terminal is connected to the bottom line of the circuit. The top, positive, end is connected to the left end of a resistor, R1. The right end of R1 is connected to the top end of R2. The bottom end of R2 is connected to the bottom line. The junction of R1 and R2 connects to the left, negative, end of a battery, E2. The right, positive, end of E2 connects to the left end of R3. The right end of R3 connects to the top end of R4. The bottom of R4 connects to the bottom line. The junction of R3 and R4 connects to the left end of R5. The right end of R5 connects to the upper output terminal. The lower output terminal connects to the bottom line of the circuit. Here is where the circuit begins to be different from Figure 1.5. There is a semicircle with an arrowhead indicating that I1 flows clockwise through E1, R1, and R2. Another semicircle and arrow head shows I2 flowing clockwise through R2, E2, R3, and R4. Another semicircle indicates that a current I3 is flowing through R4, R5, and the open circuit of the output terminals. I3 must be equal to zero because current cannot flow through an open circuit. Polarity markings on R1 and R3 indicate that the left ends are positive. Polarity markings on the left side of the vertical resistors R2, and R4, indicate that the upper end is positive. Polarity markings on the right side of the vertical resistors R2, and R4, indicate that the lower end is positive. R5 has no polarity markings. Each of the two batteries have a plus sign next to the positive terminal and a minus sign next to the negative terminal. End verbal description.