3. Precision measurements in low-frequency metrology laboratories

Voltages between 200 mV and 1,000 V

This type of measurement presents no particular difficulty. They are generally carried out directly by means of a thermal converter (consisting, for example, of a semiconductor thermoelement) associated with a DC voltage source and a DC voltage voltmeter used to mark the output voltage.

The main causes of uncertainty, apart from those arising from the source to be characterized, stem from the following components:

• connecting the reference converter ;

• connecting the dc voltage generator ;

• long-term drift of the reference converter ;

• long-term drift of the DC voltage generator ;

• stability of DC voltage...