Question 1

In the accompanying figure, when the current flow to the coil stops, the relay ____ and contact M reopens. &#160;&#10; &#10;A) energizes&#10;B) deenergizes&#10;C) opens&#10;D) shorts

Accepted Answer

B

Question 2

If a resistor is used to pull an input low, it causes the gate to have a voltage drop at its output.

Accepted Answer

A resistor used to pull an input low will cause the gate to have a voltage drop at its output because the resistor will limit the current that can flow through the gate. This will cause the voltage at the output of the gate to be lower than the voltage at the input.

Question 3

In the stop-start pushbutton circuit, when the start button is pushed, current flows through the relay coil and normally closed overload contact to the power source.

Accepted Answer

When the start button is pushed in a stop-start pushbutton circuit, current indeed flows through the relay coil and the normally closed overload contact, completing the circuit to the power source. This action energizes the relay coil, causing the contacts to change state and allow for the control of the connected load.

Question 4

If a motor becomes ____, it causes too much current to flow through the circuit.&#10;A) overloaded&#10;B) striped&#10;C) out-of-phase&#10;D) slip-biased

Accepted Answer

When a motor becomes overloaded, it draws more current than it is designed to handle, causing excessive current flow through the circuit. This can lead to overheating and potential damage to the motor and circuit components.

Question 5

In the accompanying figure, when current flows through the relay coil M, the contacts connected in ____ with the start button close. &#160;&#10; &#10;A) series&#10;B) link&#10;C) parallel&#10;D) station

Accepted Answer

The answer of In the accompanying figure, when current flows...

Question 6

The circuit continues to operate until the stop button is pushed and breaks the circuit to the ____.&#10;A) transformer&#10;B) switch&#10;C) coil&#10;D) capacitor

Accepted Answer

The answer of The circuit continues to operate until the...

Question 7

When the normally open pushbutton is pressed, it causes a low to be produced at the input of a(n) ____.&#10;A) diac&#10;B) triac&#10;C) inverter&#10;D) transformer

Accepted Answer

A normally open pushbutton, when pressed, completes a circuit. If this action is meant to produce a low signal at the input of a device, an inverter is the correct choice. An inverter flips the input signal, so a high (from the unpressed state due to pull-up resistor, for example) becomes a low when the button is pressed and the circuit is completed. Diacs and triacs are used for alternating current (AC) switching, and transformers are used to change the voltage levels, not to invert signals.

Question 8

When using TTL logic, inputs are always pulled low with a resistor as opposed to being pulled high.

Accepted Answer

In TTL logic, inputs can be pulled either low or high with a resistor, depending on the desired default state. Pull-up resistors are used to ensure a default high state, while pull-down resistors ensure a default low state.

Question 9

To prevent a gate from assuming either a high or low condition, gate inputs must always be connected to a definite low.

Accepted Answer

To prevent a gate from assuming an undefined state, gate inputs should not be left floating but can be connected to either a definite high or a definite low, depending on the desired default logic state.

Question 10

When a current greater than normal flows through the overload heater, it causes the heater to produce more heat than it does under normal conditions.

Accepted Answer

The overload heater is designed to simulate the thermal characteristics of the motor it protects. When a current greater than normal flows through it, the heater generates more heat, mimicking the excessive heat that would be generated by the motor under overload conditions. This triggers the overload protection mechanism to open the circuit and protect the motor from damage.

Deck 47: Design of Circuit 3 Solid State Pushbutton Control