Specifications

two signals. For example, on a 2125A, two 1 MHz sine waves can differ in frequency by 1 part in 10

and the Lissajous pattern will move on the screen, telling you the frequencies are slightly different.

The 2125A in component test mode uses the XY display mode.

Component test

The B&K 2125A oscilloscope provides a component test banana jack. This jack enables a user to

quickly test components in-circuit (the circuit must be powered off). Both passive components like

resistors, capacitors, and inductors can be tested as well as many active semiconductor components.

Applying the component test signal from the scope (about 6.3 Vrms) to a component results in the

scope displaying the applied voltage along the horizontal axis of the screen and the current through the

component on the vertical axis. For more details, do a web search on "octopus tester" and you will find

a number of circuits that demonstrate the technique.

The COMP TEST switch puts the scope into XY mode. This results in a current versus voltage plot. The

pattern seen on the scope helps identify the type of component and determine whether it is working

correctly or not.

Some of the patterns (sometimes called “analog signatures”) you might see on the screen are:

Figure 14

If the expected pattern isn't seen on the scope, that component is suspect or out of the measurement

range of the component test feature.

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