CRO Front Panel Controls

The Front Panel and User Controls in a CRO : 

The front panel of a single trace CRO is shown below. This CRO uses a CR Tube of 8 X 10 cm size. The front panel controls can be seen in Figure. To the right top we find three sockets marked with a square wave, a triangular wave and a sine wave near them. From these sockets we can take voltage of the corresponding waveform for calibration work. Just below the three sockets is the intensity control. Underneath intensity control we have the focus control. The astigmatism, trace rotation controls are below the focus control. The main on off switch is located below the trace rotation control. A LED indicator is provided to indicate the "switched on" condition of the instrument.

The rest of the control panel is divided into two sections. To the left of the panel we have the vertical section and the horizontal section is on the right hand side. In the vertical section to the left side the vertical input socket is provided. The mode switch / input selector is below the vertical input socket marked A.C. ground and D.C. Depending on the nature of the input signal we select the position of the switch and each time when the switch is operated ground connection is established to discharge the input attenuator as explained in vertical section of chapter this. The coarse attenuator for the vertical amplifier is marked VOLTS/CM and has 12 steps; 5 mV/cm to 20 V/cm. The fine attenuator is located above the coarse attenuator slightly towards the right side. The vertical shift control is to the left of the vertical control just below the CRT frame. A magnification switch with markings X 1 and X 5 is below the coarse attenuator that magnifies the input signal. A switch marked CT (component tester) OSC (oscilloscope) is just below the vertical mode switch. This switch converts the oscilloscope to a component tester when depressed.

In the horizontal section of the control panel, below the CRT frame we have horizontal shift control. The Fine frequency control is slightly to the left and below this control to right is the coarse frequency control marked in TIME/CM. These two controls vary the sweep frequency. A magnifier (multiplier) switch is provided below the coarse frequency switch with markings X I and X 5. The various modes as marked at the switch positions, in which the sweep could be operated, are seen near the push type switch column. Above this switch column is the trigger level control. The external trigger pulses or X input signals can be given in, through the socket below the switch column. Below the X input socket is an attenuator control that adjusts the X input signal under external mode. A LED is provided to the left of the X attenuator to indicate if the CRO is in Triggered mode.

The C B E terminals and an additional terminal are meant for utilizing the CRO for the component tester, transistor tester functions. These terminals along with a GND (ground) terminal are located just below the vertical section of the control panel.

No comments:

Post a Comment