World first handheld LCD multimeter Danameter for collector

World first handheld multimeter Danameter with LCD display. Vintage DVM (47 years)

Working fine.
Maker: Dana Laboratories, Inc. USA.
With manual and schematic.

Dana made another mark in DVM history by offering, in the early 1970s, the first successful handheld DVM,
the Danameter. A British company, Sinclair Radionics, had introduced a handheld DVM using light-emitting diodes.
But to conserve battery power, the LEDs were run with so little brightness they were hard to read.
The instrument did not survive in the marketplace.
The Danameter, in contrast, used a power-thrifty 3-1/2-digit liquid-crystal display. DVM manufacturers had begun
to use the term "half digit" for a display with "1" as the first digit. A three-digit display reading up to 999
moved up to become a 3-1/2-digit display, reading up to 1,199 for 20 percent over-range.
Though Dana was sailing along briskly, a new and very tough competitor, Hewlett-Packard, began making waves
in the increasingly crowded DVM market. By 1979, co-founder Bishop felt that Dana no longer had anything
sufficiently proprietary to compete against HP long term. He sold the company to Racal, a British concern,
and Racal-Dana exited the DVM business in 1981. Bishop is now chairman of a successful microwave-counter business
he acquired, EIP Microwave, which competes with HP.
Hewlett-Packard began its assault on the DVM market in 1958 with the rack-mount model 405AR, designed by Ted
Anderson and Noel Pace. Selling for $825, the autoranging, autopolarity instrument displayed dc-voltage measurements
from 1 mV to 999 V on three one-inch-high Nixie tubes. It provided coded output for data loggers.
Operation was based on a simple ramp circuit. The attenuated signal was compared to a linear ramp, and when
balance was reached a gate closed and the number of clock pulses gated out during the rise of the ramp was counted.
The count was proportional to the input voltage.
In the mid-1960s, Fairchild Instrumentation introduced a small benchtop DVM using dual-slope integration, a
technique developed by Fairchild's Steve Amman. Many later digital multimeters and digital panel meters adopted
the dual-slope technique, but the Fairchild DVM did not survive in the marketplace.
The HP DVM was developed in HP's hometown, Palo Alto. In 1960, HP opened a facility in Loveland, its first
manufacturing plant outside California and the new home for the company's voltmeters.