The Operational Amplifier

Chapter The Operational Amplifier

Complete Electronics Self Teaching Guide with Projects
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Complete Electronics Self Teaching Guide with Projects

  • CHAPTER 8 TRANSISTOR AMPLIFIERS370NOTE Choose the value of CS so that its reactance is less than 10 percent of RS at the lowest frequency you need to amplify. The DC load for the JFET is RD plus RS. The AC load is RD only because CS bypasses the AC signal around RS, which keeps the DC operating point stable. The use of CS reduces the gain slightly be-cause you now use a smaller RD to calculate the AC voltage swings at the output.QUESTIONSA. What is the value of RS? B. What is the value of RD? C. What is the value of CS? Assume f 5 1 kHz. D. Calculate the peak-to-peak Vout for Vin 5 0.5 Vpp. E. What is the voltage gain? ANSWERSA. R2 volts3mA667 ohmsS55B. R12 volts3mA4kD55VC. XCS 5 66.7 ohms, CS 5 2.4 μFD. The AC drain current will still vary from 3.8 to 2.3 mA, as in problem 37. The volt-age across RD is now 6 Vpp because RD is 4 kΩ. The output voltage is also 6 Vpp.E. AV5 2 5260512 The gain is 12.THE OPERATIONAL AMPLIFIER 43  The operational amplifier (op-amp) in use today is actually an integrated circuit (IC). This means that the device has numerous transistors and other components constructed Book Author c08 V1 07/04/2012 3:18 PM c08.indd 3707/4/2012 3:20:28 PM