Browse Prior Art Database

Oscilloscope Pre-Trigger Circuit for Transient Testing

IP.com Disclosure Number: IPCOM000050524D
Original Publication Date: 1982-Nov-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Driscoll, CD: AUTHOR

Abstract

The figure illustrates in block diagram form a switching circuit developed for observing the effect of transient overloads on switching power supplies. In order to observe current or voltage in a device under overload conditions, it is generally necessary to store the history of the overload in a memory oscilloscope. In order to do this, the oscilloscope must be triggered and then the overload applied to the device so the triggering of the oscilloscope occurs at exactly the right time to capture all of the transient behavior. This is a difficult operation to perform manually and will often be unsuccessful.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 53% of the total text.

Page 1 of 2

Oscilloscope Pre-Trigger Circuit for Transient Testing

The figure illustrates in block diagram form a switching circuit developed for observing the effect of transient overloads on switching power supplies. In order to observe current or voltage in a device under overload conditions, it is generally necessary to store the history of the overload in a memory oscilloscope. In order to do this, the oscilloscope must be triggered and then the overload applied to the device so the triggering of the oscilloscope occurs at exactly the right time to capture all of the transient behavior. This is a difficult operation to perform manually and will often be unsuccessful.

This circuit generates a trigger signal and, after an adjustable time delay, applies the overload to the power supply or device under test. This permits the transient behavior of the switch current to be observed both before, during, and after the overload is applied. It guarantees that no cycles of power will be missed.

Using the new circuit, the time delay and the oscilloscope triggering level can be set up by applying an overload to a current-limited laboratory power supply until proper operation of the delay circuit and the oscilloscope is observed. Then, leaving the oscilloscope and delay circuit thus adjusted, the overload can be applied to the device under test without further adjustment of the circuit.

In the figure, a latch 1 interfaces mechanical switches Sl and S2 to insure that contact bounce will not affe...