If the resistance measured across terminals LM in Fig. 2.30 is 15 ohms, what is the value of R____________?
Show answer Hide answer
Answer: C. 30 Q
Explanation
Terminal resistance formulas for series and parallel networks are used to work backward from total resistance. Setting up algebraic equations for the resistor network matches the measured fifteen ohm terminal resistance. Solving the resulting equation for the unknown variable R yields a precise value of thirty ohms. Parallel resistances are calculated by taking the reciprocal of the sum of reciprocal resistance values. Series resistances add together directly through simple algebraic summation. Circuit reduction techniques help determine unknown component values from external terminal measurements.
Maintenance technicians use resistance measurements to verify component values and detect broken circuit traces. Manufacturing test fixtures rely on calculated network equations to verify resistor assembly tolerances. Troubleshooting complex industrial controls often requires solving equivalent resistance network problems. Ten ohms produces a different equivalent terminal resistance that contradicts the fifteen ohm measurement. Twenty ohms fails to satisfy the simultaneous series-parallel equation balance for the network. Option d proposes forty ohms, which results in an equivalent resistance higher than the measured value.
- Subject
- Engineering
- Category
- Electrical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. What are the defining characteristics of an ideal operational amplifier
Show answer Hide answer
Answer: A. Ri=∞ ,A=∞ ,R0=0
Infinite input impedance ensures that zero input current flows into the operational amplifier terminals. Infinite open-loop gain allows negative feedback to precisely control the closed-loop gain of the circuit. Zero out...
Q2. How is the closed-loop voltage gain of an inverting amplifier determined______________?
Show answer Hide answer
Answer: C. The feedback resistance divided by the input resistance
Inverting amplifier closed-loop gain equals negative feedback resistance over input resistance. Feedback resistor determines signal amplification magnitude in inverting op-amp circuits. Input resistance sets the scaling...
Q3. Connecting the (+) terminal of an inverting op-amp to ground forces the (–) terminal to_____________?
Show answer Hide answer
Answer: B. Be virtual ground
Inverting op-amp configurations connect the non-inverting terminal directly to a ground reference point. Negative feedback forces the differential voltage between the inverting and non-inverting terminals to approach zer...
Q4. Which of the following holds true for an ideal operational amplifier?
Show answer Hide answer
Answer: C. The current from output terminal is zero
An ideal operational amplifier draws zero input current because its input impedance is infinitely large. Infinite input impedance prevents the amplifier from drawing any electrical current from connected signal sources....
Q5. How many op-amps are required to implement the relationship Vo = V1?
Show answer Hide answer
Answer: D. 1
Unity-gain buffer circuits achieve an output voltage exactly equal to input voltage. Non-inverting configuration with one hundred percent feedback realizes Vo equals V1. Single operational amplifier is sufficient to cons...
Q6. To achieve maximum power transfer, how should the source's internal resistance relate to the load_____________?
Show answer Hide answer
Answer: A. equal to load resistance
Maximum power transfer theorem proves that load resistance must equal internal source resistance. Any deviation from this matching condition results in less power being delivered to the external load. Differentiating the...