What is the frequency of this 555 astable multivibrator? 278 Hz 178 Hz 78 Hz 8 H

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Question
What is the frequency of this 555 astable multivibrator?
Options
A. 278 Hz
B. 178 Hz
C. 78 Hz
D. 8 Hz

Correct Answer

178 Hz

Operational Amplifiers problems

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2. With negative feedback, the returning signal
Options
A. is proportional to the output current
B. is proportional to the differential voltage gain
C. opposes the input signal
D. aids the input signal

3. The input offset current equals the
Options
A. average of two base currents
B. collector current divided by the current gain
C. difference between two base-emitter voltages
D. difference between two base currents

4.
Decreasing the gain in the given circuit could be achieved by
Options
A. reducing the amplitude of the input voltage
B. increasing the value of the feedback resistor
C. increasing the value of the input resistor
D. removing the feedback resistor

5. A differential amplifier has a common-mode gain of 0.2 and a common-mode rejection ratio of 3250. What would the output voltage be if the single-ended input voltage was 7 mV rms?
Options
A. 1.4 mV rms
B. 650 mV rms
C. 4.55 V rms
D. 0.455 V rms

6. If the gain of a closed-loop inverting amplifier is 3.9, with an input resistor value of 1.6 kilohms, what value of feedback resistor is necessary?
Options
A. 6240 ohms
B. 2.4 kilohms
C. 410 ohms
D. 0.62 kilohms

7. When a capacitor is used in place of a resistor in an op-amp network, its placement determines:
Options
A. open- or closed-loop gain
B. integration or differentiation
C. saturation or cutoff
D. addition or subtraction

9. The magnitude of closed-loop voltage gain (A_cl) of an inverting amplifier equals:
Options
A. the ratio of the input resistance to the feedback resistance
B. the open-loop voltage gain A_ol
C. the feedback resistance divided by the input resistance
D. the input resistance

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