HP 2804A Quartz Thermometer Specifications

HP 2804A Quartz Thermometer Operating and Service Manual

HP 2804A Quartz Thermometer manual from Keysight

HP 2804A Quartz thermometer  Forum

The HP 2804A Quartz Thermometer allows you to easily measure temperature with exceptionally high accuracy and resolution. Absolute accuracy is ±40 millidegrees Celsius over the range of — 50 °C to 150°C, NBS traceable to IPTS-68.

The useable resolution of 0.0001 °C allows you to measure temperature changes that could not be detected by other digital thermometers.

The HP 2804A can be used with one or two temperature sensing probes. The temperature of either probe, or their difference, can be measured and displayed under pushbutton control.

Display resolution is selectable from 0.01 to 0.0001 °C (0.1 to 0.001 ° F) by pushbuttons.

An internal switch allows you to easily select measurement in the Celsius or Fahrenheit temperature scale.

Temperature is measured and displayed automatically with the microprocessor and electronics provided in the HP 2804A package.

There is no need to balance a bridge, perform calculations using resistance- or voltage-temperature tables or curves, or to use calibration correction tables. The only adjustment necessary to remove effects of thermal history on the sensor is a simple ice point or triple point calibration adjustment using the front panel thumbwheel switches.

How It Works

The HP 2804A temperature sensor is a quartz crystal whose precise angle of cut gives a stable and repeatable relationship between resonant frequency and temperature.

Each quartz sensor is individually calibrated at the factory over the full temperature range. The calibration data for each sensor is processed and stored in a calibration module which is supplied with the probe.

In operation, a microprocessor in the thermometer performs the complex control and calculation operations to accurately measure temperature from the quartz sensor frequency and probe calibration information in the calibration module.

The microprocessor also performs self-checks to detect fault conditions.

If a problem occurs that would give an improper measurement, an error message is displayed to indicate the source of the problem.