Timing with the Oscilloscope

The various times involved in a relay s operation can be measured with an oscilloscope, even though they are just thousandths of a second long. The circuit is shown in Fig. 12.4. An internal circuit diagram of the relay itself is printed on its case. The resistor and capacitor hooked up by the experimenter will slow some parts of the operation for easier observation on the scope. 

The POSITION Y knob can be used to move the bright line up or down to the middle of the screen. The POSITION X knob can adjust the starting point of the line, so it is barely to the right of the left edge of the screen. 

Following are some things that are different from those on pages 76 and 77. 

A second BNC cable is attached to the EXT TRIG socket, for external triggering. (The dashed- and dotted-line wires in Fig. 12.4 are not attached yet.) 

TRIGGER LEVEL knob should be slightly positive, about 1 00 o clock. 

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