Chapter 7 · MCQ Read Mode

Electronic Devices, Circuits and Machines for BME

The thermal voltage of a semiconductor junction at room temperature is approximately:

Which component cannot practically be fabricated in a monolithic integrated circuit?

The small-signal dynamic resistance of a diode carrying 1 mA, with an ideality factor of 1, is approximately:

Diffusion capacitance in a diode is significant when the diode is:

For a bipolar transistor operating in the active region, the transconductance is given by:

If a transistor has alpha equal to 0.98, its beta is approximately:

A transistor operating with both junctions forward biased is in the:

The common collector (emitter follower) configuration is used principally as:

Voltage-divider bias with an emitter resistor is preferred for a BJT amplifier because it:

A JFET is described as a depletion-mode device because it:

The drain current of a JFET in the pinch-off region follows:

A MOSFET operating with VDS much smaller than the gate overdrive behaves as:

Compared with a bipolar transistor at the same bias current, a MOSFET has:

The maximum theoretical efficiency of a class B push-pull power amplifier is:

Crossover distortion is characteristic of which amplifier class, and is removed by which modification?

A class C amplifier can only be used with a tuned load because:

For an ideal operational amplifier with negative feedback, the two rules used in analysis are that:

An op-amp with a 10 kilohm input resistor and a 100 kilohm feedback resistor in the inverting configuration has a gain of:

The common-mode rejection ratio of a differential amplifier is improved principally by:

Which op-amp circuit provides very high input impedance with the gain set by a single external resistor?

According to the Barkhausen criterion, sustained oscillation requires a loop gain of:

A Wien bridge oscillator requires the amplifier to have a gain of exactly:

In an operational amplifier astable multivibrator with equal positive-feedback resistors, the period of oscillation is approximately:

The CMOS inverter relaxation oscillator works because a CMOS inverter has:

The principal disadvantage of the simple CMOS inverter RC oscillator is that its frequency:

Which filter approximation should be chosen when preserving the shape of a pulse-like biosignal such as the ECG is most important?

The RMS value of a sinusoidal voltage with a peak value of 325 V is approximately:

In a purely capacitive AC circuit, the current:

A pure inductor connected across an AC supply consumes:

At series resonance in an R-L-C circuit, the impedance is:

A parallel resonant circuit at its resonant frequency presents:

The quality factor Q of a resonant circuit is related to bandwidth by:

Three equal resistances of 9 ohms connected in delta are equivalent to a star connection of:

In a balanced star-connected three-phase system, the relationship between line and phase quantities is:

Total power in a balanced three-phase load is given by:

In a balanced three-phase four-wire system, the current in the neutral conductor is:

The neutral conductor of a three-phase four-wire distribution system must never be fused because:

Using the two-wattmeter method on a balanced load, the two wattmeters read equal values. The power factor is:

A load draws 10 A at 230 V with a power factor of 0.8 lagging. The true power is:

The ripple factor of a full-wave rectifier without a filter is:

The peak inverse voltage across each diode in a bridge rectifier is:

The ripple frequency at the output of a full-wave rectifier fed from a 50 Hz supply is:

A capacitor input filter gives its best smoothing when:

The rectification efficiency of a full-wave rectifier is approximately:

A Zener diode of about 5.6 V is often preferred as a voltage reference because at that voltage:

In designing a shunt Zener regulator, the series resistor must be chosen so that:

The efficiency of a linear series regulator is fundamentally limited because:

Switching mode power supplies are widely used in medical equipment despite the drawback of:

A bandgap voltage reference achieves temperature stability by:

A constant current diode is constructed from:

A charge-balance voltage-to-frequency converter achieves high linearity because:

Voltage-to-frequency conversion is commonly used to transmit an analogue signal across a patient isolation barrier because:

Ohm's law does not apply to which of the following?

An ideal current source has an internal resistance of:

Three resistors of 6 ohms each are connected in parallel. The equivalent resistance is:

Cells are connected in parallel rather than in series principally in order to:

Kirchhoff's current law is a direct consequence of the conservation of:

The superposition theorem may NOT be used to calculate:

When applying the superposition theorem, an ideal voltage source is replaced by:

The Thevenin equivalent voltage of a network is measured as:

A network has a Thevenin equivalent of 12 V in series with 4 ohms. Its Norton equivalent is:

Maximum power is transferred to a load when the load resistance equals the source resistance, at which point the efficiency is:

In the mesh resistance matrix of a passive network, the off-diagonal elements are:

How many independent equations are needed for nodal analysis of a circuit with 5 nodes?

A battery of emf 12 V and internal resistance 0.5 ohms supplies a current of 4 A. Its terminal voltage is:

Eddy current loss in a transformer core is proportional to the square of the:

Hysteresis loss in a magnetic core is proportional to:

Silicon is added to transformer steel principally to:

The emf induced in a transformer winding is given by:

A transformer connected to a DC supply will:

A transformer has maximum efficiency when:

An autotransformer is unsuitable for isolating patient-connected equipment because it:

The component of a DC generator that converts the internally generated alternating emf into a unidirectional output is the:

The generated emf of a DC generator is proportional to:

The starting current of a DC motor is very large because at standstill:

The torque developed by a DC motor is proportional to:

A DC series motor must never be started on no load because:

Which motor is chosen where nearly constant speed is required regardless of load?