Abstract: An electrical thermometer having a digital display comprises a flat, rectangular casing a principal face of which is provided with the digital indicating device, and a measuring probe which is connected with a voltage-fed electrical building block of an electronic analyzer and display unit. The thermometer is devised to be smaller and more compact than known devices and affords a safe operation even under disadvantageous environmental conditions. To this end, the voltage source of the electronic analyzer and display unit block is a solar cell arranged in a principal face of the casing. The presence of this solar cell affords a particularly advantageous permanent guarantee of the energy supply. Moreover, it offers the advantage of a construction of the thermometer casing which is free from the need for a receptacle opening for a battery and can thus be manufactured water-tight in a simple manner.