Abstract: The generation and monitoring of a load-independent output current for a level meter, pressure gauge, flowmeter or evaluation device are described. A current that is equal or unequal to the measuring current, but inverted relative thereto, can be generated continuously or within certain time intervals in a switching circuit that is realized independently of the network generating the measuring current. The generated current can be fed into the measuring circuit at a comparison point and added. The compensation principle makes it possible to determine whether the measuring current corresponds to the nominal value, wherein a testing current is fed into the first electric circuit by means of a second switching circuit that contains a second current source. A certain expectancy value of a voltage to be tapped can be calculated in dependence on the testing current being fed in and the nominal value.

Abstract: The generation and monitoring of a load-independent output current for a level meter, pressure gauge, flowmeter or evaluation device are described. A current that is equal or unequal to the measuring current, but inverted relative thereto, can be generated continuously or within certain time intervals in a switching circuit that is realized independently of the network generating the measuring current. The generated current can be fed into the measuring circuit at a comparison point and added. The compensation principle makes it possible to determine whether the measuring current corresponds to the nominal value, wherein a testing current is fed into the first electric circuit by means of a second switching circuit that contains a second current source. A certain expectancy value of a voltage to be tapped can be calculated in dependence on the testing current being fed in and the nominal value.

Abstract: The method for determining the energy content value (EIW) of electrochemical energy stores (1) by measuring the terminal voltage (U.sub.KL) of an energy store (1) recognizes at least one reference value (BW) that is formed from a sum current (EI) flowing in the energy store (1) in a specific time unit (dt) and in a specific operating voltage range (BSB) and/or from reaction values of the energy store (1) such as the internal resistance, the inside temperature and the acid density; dependent on a defined terminal voltage (U.sub.KL) in the operating voltage range (BSB) and on a defined energy content value (EIW) in an energy content range (EIB), this reference value (BW) thereby represents a function value. The measured terminal voltage (U.sub.KL) referred to the function value (FW) corresponds to a specific energy content value (EIW) in the energy content range (EIB).