Question 1

The amount of gate current supplied to the SCR is determined by the amount of resistance connected in the gate circuit, and the difference in voltage between the power supply and the terminal voltage of the battery.

Accepted Answer

The gate current is determined by the voltage difference between the gate and cathode terminals, and the resistance in the gate circuit.

Question 2

The silicon-controlled rectifier (SCR) is made by bonding four layers of semiconductor material together to form a pn-pn junction.

Accepted Answer

The silicon-controlled rectifier (SCR) indeed consists of four layers of semiconductor material that form a pn-pn junction, which allows it to act as a switch that can turn on or off electrical power in a circuit.

Question 3

The SCR operates very similarly to a(n) ____, which is controlled by a set of pushbuttons and is latched with holding contacts.&#10;A) transistor&#10;B) transformer&#10;C) inverter&#10;D) relay

Accepted Answer

SCRs (Silicon Controlled Rectifiers) operate in a manner similar to relays in that both can be controlled by a low-power signal and maintain their state (on or off) without continuous control signal, akin to how a relay can be latched through holding contacts.

Question 4

The gate-turnoff SCR is also known by the name ____.&#10;A) sink controlled switch&#10;B) gate controlled switch&#10;C) block controlled switch&#10;D) current controlled switch

Accepted Answer

The gate-turnoff SCR is known as a gate controlled switch because its operation (turning on and off) is controlled by the gate terminal.

Question 5

SCRs are known as the workhorses of industrial electronics because of their ability to control hundreds of volts and amps.

Accepted Answer

SCRs (Silicon Controlled Rectifiers) are indeed known as workhorses of industrial electronics due to their robustness and capability to control large amounts of power, specifically hundreds of volts and amps, making them ideal for applications requiring high power control.

Question 6

The amount of current flowing through the anode-cathode circuit needed to keep the SCR turned on is called the ____ current.&#10;A) charging&#10;B) saturation&#10;C) holding&#10;D) falling

Accepted Answer

The holding current is the minimum amount of current that must flow through the SCR (Silicon Controlled Rectifier) to keep it in the conducting state. Once the SCR is triggered into the on state, the current must not fall below this level; otherwise, the SCR will turn off.

Question 7

SCRs designed to control small amounts of power require a gate current of ____.&#10;A) a few microamps&#10;B) a few dozen microamps&#10;C) several hundred milliamps&#10;D) several thousand milliamps

Accepted Answer

SCRs (Silicon Controlled Rectifiers) designed for controlling small amounts of power typically require a gate current of a few microamps to trigger the device.

Question 8

The gate-turnoff SCR operates in a fashion similar to a common SCR in that it can be turned off with a gate pulse that is negative with respect to the cathode.

Accepted Answer

A gate-turnoff SCR (GTO) can be turned off by applying a negative gate pulse, unlike a common SCR which cannot be turned off by the gate once it is conducting.

Question 9

The SCR is called a ____ because its characteristics are similar to the gas-filled thyratron tube used in industrial electronics for many years.&#10;A) thyristor&#10;B) thermistor&#10;C) transistor&#10;D) cathode

Accepted Answer

The SCR (Silicon Controlled Rectifier) is called a thyristor because its characteristics are similar to those of the gas-filled thyratron tube, which was used in industrial electronics for many years before the development of semiconductor devices like the SCR.

Question 10

SCRs can be tested with an ohmmeter by connecting the negative lead to the anode and the positive lead to the cathode.

Accepted Answer

To test an SCR with an ohmmeter, the positive lead should be connected to the anode and the negative lead to the cathode.

Deck 17: The Scr in a Dc Circuit