ELEC 1
A nickel-cadmium cell has an operating voltage of about ____ volts.
1.25
The di/dt capability of a thyristor increases when the:
gate current increases
In a UJT, intrinsic standoff ratio, η, is typically:
0.7
In an RC low-pass filter, output is taken across the ______.
capacitor
How could voltage be greater across reactances in series than the applied voltage?
Resonance
According to Gauss’ law for magnetism, magnetic field lines:
form closed loops
Which of the following instruments would be best for checking a TTL logic circuit?
Logic probe
In an SCR, anode current flows over a narrow region near the gate during ______.
about 10 μsec
The output of a separately-excited AC generator running at a constant speed can be controlled by the ______.
amount of field current
For a steady dc current, the X_L of an inductor is ______.
0 Ω.
Which of the following types of solder is best for radio and electronic use?
Rosin-core solder
The photoconductive effect in crystalline solids produce a noticeable change in the _____ of the solid.
resistance
What is the characteristic appearance of a cold solder joint?
A grainy or dull surface
What happens to the conductivity of a photosensitive semiconductor junction when it is illuminated?
The junction resistance decreases.
What is the diameter, in inches, of a #12 copper wire?
0.0808
In pure silicon, select which statements is true:
The holes and electrons exist in equal number
What is an L-network?
A network consisting of an inductor and a capacitor.
If the secondary current in a step-down transformer increases, the primary current will ____.
increase
An electrical relay is a:
Remotely controlled switching device.
For electricity to do work the electrons must:
Flow from a higher to a lower electron voltage.
A series connected C −R circuit is suddenly connected to a d.c. source of V volts. Which of the statements is false?
The current grows exponentially
Iron, rather than copper, is used in the core of transformers because iron:
Has a very high permeability.
Why is a pull-up resistor needed when connecting TTL logic to CMOS logic?
To increase the output HIGH voltage
What type of semiconductor diode varies its internal capacitance as the voltage applied to its terminals varies?
Varactor diode.
For either an RC low-pass or high pass filter,
Xc = R at the cutoff frequency.