An Automatic Recorder for Resistance Thermometry

A completely automatic recording Wheatstone bridge is designed especially for use in resistance thermometry. It is built into a standard commercial recorder, contains decade coils operated by a Geneva gear mechanism, and increases the original range of the machine 100-fold. With it a continuous record of resistance versus time is made covering a range of 0 to 100 ohms that may be easily read to 0.001 ohm±0.001 ohm. Employed in connection with a standard 25-ohm platinum resistance thermometer a temperature range of −190° to 550°C can be covered with a precision of 0.01°C±0.01°.