# Electrical Measurements Questions and Answers – Principle of Time Base Generator

This set of Electrical Measurements & Measuring Instruments Multiple Choice Questions & Answers (MCQs) focuses on “Principle of Time Base Generator”.

1. What is hold off time in a CRO?
a) time to start a ramp
b) time to end a ramp
c) time to start a unit step
d) time to end a unit step

Explanation: In a Cathode Ray Oscilloscope, the trigger circuit applies the pulse as soon as the cycle ends. The hold off time in a time base generator is defined as the time taken for the ramp signal so as to stabilise the flyback circuitry.

2. What is the wait time in a CRO?
a) time to deactivate time base generator
b) time to activate time base generator
c) time from input to output
d) time from output to input

Explanation: In a Cathode Ray Oscilloscope, the trigger circuit produces a trigger pulse. The pulse must exceed a certain reference threshold level in order to activate the time base generator. This is known as trigger threshold.

3. A trigger circuit is ___________
a) is used for triggering the input
b) is used for triggering the output
c) used with time base generator
d) used as a oscillator

Explanation: In a Cathode Ray Oscilloscope, the trigger circuit is basically used for triggering the time base generator. It triggers the time base generator and produces a ramp signal.

4. Time base generator takes certain time to begin a new cycle.
a) True
b) False

Explanation: After the end of a cycle of sweep and retrace, the time base generator takes certain amount of time to commence a new cycle. This time can be divided into two parts:
i) Hold off time and ii) Waiting time.

5. After hold off time, the time base generator is activated immediately.
a) True
b) False

Explanation: As a result of trigger threshold crossing the time base generator doesn’t immediately get activated after the hold off time. This time is known as the waiting time wherein the triggering pulses cross the trigger threshold.

6. A time base should have _________
a) non-linearity
b) ramp relationship
c) linearity
d) unit step relationship

Explanation: In a Cathode Ray Oscilloscope, a time base generator must have a linear relationship. Linearity of the order of more than 1 % across the cathode ray tube can be obtained by making use of a time base generator.

7. The horizontal amplifier in a CRO can be expanded by _________
a) 5 times
b) 15 times
c) 30 times
d) 10 times

Explanation: In a Cathode Ray Oscilloscope, the horizontal amplifier can be expanded by up to 10 times. This allows a division of 1nsec display for very high speed transient waveforms.

8. Sweep rate is controlled by a _________
a) capacitor
b) resistor
c) diode
d) inductor

Explanation: In a Cathode Ray Oscilloscope, the sweep rate is controlled by a capacitor. This is done through means of the charging current flowing through the capacitor.

Sanfoundry Global Education & Learning Series – Electrical Measurements.