26-07-2014, 10:21 AM
Recorders
[attachment=66241]
Recorders
gives graphical record of history of measurements of some physical events
Basic elements
Paper chart – to record information
Stylus- writing instrument
interfacing apparatus
Features
Limited freq. response dc – 125 Hz
Mech. Writing instrument
Some strip chart types- uses photo graphic plate – few thousand Hz
Strip Chart type
Signal conditioning to drive chart at desired rate
drives reversible motor
Event marker to mark edges of chart
Galvanometer type
Galvanometer recorder are
uses d’Arsonval’s movement
But not sensitve
Cost and size advantages
Sampling oscilloscope
So e beam has to be accelerated to high velocity KE increases, to maintain normal image
Increase in electron beam velocity easily achieved by raising the Voltage of accelerating anode
e beam with high velocity- needs greater potential for deflection – high demand on Vert. ampr.
Disadvantages of conventional type
Can store only for finite time
Trace not fine as ordinary CRt
Writing rate is less
Expensive CRT
Only one image can be stored
[attachment=66241]
Recorders
gives graphical record of history of measurements of some physical events
Basic elements
Paper chart – to record information
Stylus- writing instrument
interfacing apparatus
Features
Limited freq. response dc – 125 Hz
Mech. Writing instrument
Some strip chart types- uses photo graphic plate – few thousand Hz
Strip Chart type
Signal conditioning to drive chart at desired rate
drives reversible motor
Event marker to mark edges of chart
Galvanometer type
Galvanometer recorder are
uses d’Arsonval’s movement
But not sensitve
Cost and size advantages
Sampling oscilloscope
So e beam has to be accelerated to high velocity KE increases, to maintain normal image
Increase in electron beam velocity easily achieved by raising the Voltage of accelerating anode
e beam with high velocity- needs greater potential for deflection – high demand on Vert. ampr.
Disadvantages of conventional type
Can store only for finite time
Trace not fine as ordinary CRt
Writing rate is less
Expensive CRT
Only one image can be stored