Function of time base generator, Electrical Engineering

Q. Explain the function of time base generator in CRO.

Sol. Oscilloscopes are used to display a waveform that varies as a function of time. If the waveform is to be accurately reproduced, the beam must have a constant horizontal velocity. Since the beam velocity is function of deflecting voltage and the deflecting voltage is increased linearly with time. A voltage with this characteristic is called ramp voltage. If the voltage decreases to zero within the waveform reputedly reproduced this pattern is known as Saw tooth waveform.

During the sweep time, the beam moves from left to right across the circuit. The beam is deflected to right by the increasing amplitude of the ramp voltage and the fact that the voltage attracts the electrons during the retrace time or fly back time.

The beam returns to the left side of the    screen. The control grid is "grated off", which blanks out the beam during retrace time and prevents the undesirable signals pattern on the screen.

A continuous sweep CRO using UJT as a time base generator is shown in. the UJT is used to produce the sweep. When the power is applied the UJT is off and the changes exponentially through. The JUT emitter voltage rises towards.

And when reaches the peak voltage as shown in. the emitter to base. Diode becomes forward biased and the UJT trigger ON Which provides a low resistance discharge path and the capacitor dischargers rapidly.

The emitter voltage reaches the minimum value and JUT goes off. The capacitor, recharge and the cycle repeats.

To improve sweep linearity, two separate voltage supplies are used, a low voltages supply for UJT and a high voltage supply for the circuit. Is used fir continuous control of frequency within a range and is changed in step for range changing.

 

 

Posted Date: 7/12/2012 6:15:33 AM | Location : United States







Related Discussions:- Function of time base generator, Assignment Help, Ask Question on Function of time base generator, Get Answer, Expert's Help, Function of time base generator Discussions

Write discussion on Function of time base generator
Your posts are moderated
Related Questions
Negative test cases for testing mobile phones are: 1.taking out the SIM card and made a call  2. by invalid phone number 3. Made a call at which there is no tower signa


Illustrate the working principle, equipment used,process characteristic, advantage and disadvantage of water jet machine (WJM) (a) Illustrtae the working principle of ultrasonic

The mechanical power produced at the armature of a motor is: P = T a . (power is in watts if torque is N.m and    in rad/sec). Some of this will be lost due to friction and


Q. With a suitable block circuit, show how linear sweep voltage is generated ? The above figure shows a basic sweep waveform generator. The switching action of the switch

Define Flash Analog to Digital Converters? Parallel flash ADCs transform the analog input voltage faster as compared to other types of ADCs.  They compare the voltage in parall

a) Provide pertinent summary of the basic principles behind ECG monitoring b) Using MATLAB, provide plots of the "clean" and "noisy" ECG signals. Investigate the spectral es

Currents induced in armature conductors of a d.c. generator are alternating. To make their flow unidirectional in the external circuit, we need a commutator. Moreover, these curren

Maximum power transfer theorem