Digital multimeter with microprocessor control

Abstract

A digital multimeter includes a microprocessor control and a keyboard input. The microprocessor functions to control the display of parameters measured by the meter and displays such measured parameters. The keyboard includes switches to allow the user to select a parameter which is desired to be measured as well as a range of values for that parameter for use in measuring parameters of a device under test connected to the multimeter. The microprocessor communicates with the keyboard and functions to control a resistor and switch network to configure the multimeter to test selected parameters within selected ranges. The multimeter incorporates an overload protection function which compensates for an over-large voltage on the input leads of the multimeter, thus preventing damage to the circuit and to the multimeter.

Dependencies are inferred from the claim text.