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
Inference Rules of Explanation system How an Explanation System might work where questions like how or why are dealt with. Inference Rules use an if-statement and a then-statem

1. Introduction : Theory:  Phase angle is defined as the number of degrees separating two sine waves of the same frequency. The Phase shift is defined as any change t

Ionic Bonding Instance: NaCl. Na (Z = 11) gives up the outermost shell electron of it to Cl (Z=17) atom, so the crystal is build up of ions with the electronic structure

If the message has a spectrum where K and Wf are positive constants, sketch the spectrum of a standard AM signal that uses the message. Comment on the physical signi?cance

Q. For the circuit shown in Figure, obtain: (a) z-and y-parameters; (b) Transfer function I 2 /I 1 when V 2 = 0.

how can i do a question concerning a transfer function

What is the maximum memory size that can be addressed by 8086? In 8086, an memory location is addressed by 20 bit address and the address bus is 20 bit address and the address

Define The universal property of NAND and NOR Gates? The NAND and NOR gates are called universal gates, because any gate can build by using these two gates. The univers

Mention how do the DIV & IDIV instructions differ in their functionality DIV: Unsigned numbers division and IDIV: Signed number division.

What is memory paging? The memory paging mechanism located inside the 80386 and above permits any physical memory location to be assigned to some linear address.