Printed circuit board and design of the case with a sealant around a cover were developed. The price was an important criterion; therefore cable inputs with IP65/66 were installed instead of sockets. Precision operational amplifiers with multiway low-noise potentiometers were installed on the board. Output current for the bridge circuit and rate of signal amplification and its zero-offset can be set. The required cost price and a very low noise level were achieved. The task was implemented in time; 10 prototypes were produced.