Hp 3440A
History of HP’s DVM (digital voltmeter), there first ones sold for $2,300 (1953) and now you can get them for $5! –

“It may seem odd dedicating a page of this computer-oriented Web site to digital voltmeters, but digital instrumentation played a key role in the success of the HP 9825 desktop computer. The HP 9825 represented a real breakthrough in instrumentation control. Without digital instrumentation, there would have been nothing to control and the HP 9825 would not have succeeded half as well as it did.

Although Hewlett-Packard, which was founded as an instrumentation company, achieved many firsts in the test and measurement industry, the digital voltmeter (DVM) was not one of these firsts. Not by a long shot. In fact, HP got behind the differential voltmeter, an analog instrument eventually obsoleted by the DVM. HP didn’t enter the DVM market until 1958, but that’s getting ahead of this story.”Link.

Related:

  • Single-digit Nixie, Oscilloscope CRT a Weston … – Link.