A test instrument which is designed to give visual indications on an lcd display or a cathode ray tube of instantaneous values and variations in electrical voltage. it can also be used to indicate any quantity which can be converted into terms of electrical potential. it may include an integral pulse generator, the output of which can be used to trigger an external component; be triggered by pulses from an external source, or it may utilize an lcd display or a special type of multigun cathode ray tube and circuitry which permits a trace(s) to be sustained and displayed indefinitely, and the trace(s) may be erased when desired. for items which are not separable and operable when detached from equipment of which they are a part (built into operational equipment), see indicator (2) (as modified); monitor (as modified); and recorder (as modified). see also oscillograph.