For the bridge circuit shown, what must the value of R4 be in kilohms to set V12, the voltage across R5, equal to zero? (Hint: Use Thevenin equivalents to solve this problem more easily.) Use: Vx = 4.5V, R1 7.4kQ, R2 = 5kQ, R3-4 9kQ, R4-2.5K and R5 = 8.6kQ. Answer