###### Electronic Principles

312 SOLVED PROBLEMS

Question: 5.13

## Figure 5-22b is a continuity tester. After you turn off all the power in a circuit under test, you can use this circuit to check for the continuity of cables, connectors, and switches. How much LED current is there if the series resistance is 470 Ω? ...

When the input terminals are shorted (continuity),...
Question: 23.6

## A 12-bit ADC system is used to digitize a 0-V to 5-V analog dc voltage. Determine the resolution of the ADC system and the voltage step size. ...

Resolution = # of bits Resolution = 12, which prov...
Question: 23.5

## A mixing tank, like the one shown in Fig. 23-18, is being filled with solution. An ultrasonic sensor is located at the top of the tank. The tank is 10 feet in diameter and 15 feet tall. The mixing process in the tank requires 1021 ft3 of solution. Solve for the required height of solution ...

Volume of a cylinder: $V = πr^2 h$ Wh...
Question: 23.4

## The operational amplifiers used in Fig. 23-12 have an Rin of 3 MΩ, an RCM of 200 MΩ, and an open-loop voltage gain of 175,000. Solve for Zin(CL), AV(CL), and vref. ...

Z_{in(CL) }= (1 + A_{VOL}B)R_{in} ∥ R_{CM}[...
Question: 23.3

## The RTD shown in Fig. 23-7 has a resistance ranging from 1 kΩ to 1.1 kΩ between 0°C and 100°C. The 741 operational amplifiers used have these values: AVOL = 100,000, Rin = 2 MΩ, and RCM = 200. Utilizing the differential amplifier with buffered inputs introduced in Chap. 18, Sec.18-4, “Differential ...

The buffer amplifiers provide very high input impe...
Question: 18.1

## One application for Fig. 18-6 is in a squelch circuit. This kind of circuit is used in communication receivers to reduce listener fatigue by having a low voltage gain when no signal is being received. This way, the user does not have to listen to static when there is no communication signal. ...

With the equations given in Fig. 18-6, the maximum...
Question: 18.2

## When we need to vary the amplitude of an out-of-phase signal, we can use a circuit like the one in Fig. 18-10. If R1 = 1.2 kΩ and R2 = 91 kΩ, what are the values of the maximum and minimum voltage gain? ...

With the equation given in Fig. 18-10, the maximum...
Question: 18.3

## If R = 1.5 kΩ and nR = 7.5 kΩ in Fig. 18-12, what is the maximum positive voltage gain? What is the value of the other fixed resistance? ...

The value of n is: n=\frac{7.5 \ k\Omega }{...
Question: 18.4