Abstract: A method of producing a solid electrochrome element comprises depositing a layer of an electrochrome material onto a substrate having an electrically conducting layer in a vacuum from about 10.sup.-6 mm Hg to about 5.10.sup.-2 mm Hg at a vaporization temperature of from about 1,200.degree. C. to about 2,500.degree. C., the substrate temperature being maintained within a temperature range from about room temperature to about 500.degree. C.sub.x ; and coating the electrochrome layer with a layer of insulating material vaporized in a vacuum from about 10.sup.-7 to about 10.sup.-4 mm Hg at a temperature of from about 1,300.degree. C. to about 2,000.degree. C., the substrate temperature being kept within a temperature range from about room temperature to about 300.degree. C. The solid electrochrome elements produced by this method and characterized by a fast speed of action.

Abstract: The proposed electrochromic indicator can be used in clock dials and band selector indicators of radio receivers and it comprises electrochromic cells placed in series to form a closed circuit. Each point of connection of the leads of said electrochromic cells is coupled via a respective switching means to the terminals of a d.c. voltage source. Each switching means comprises two transistors of different conductivity, whose emitters are connected to a respective point of connection of the leads of the electrochromic cells. The collector of one of the transistors is connected to the negative terminal of the d.c. voltage source, and the collector of the other transistor is connected to the positive terminal of that source. The bases of the transistors are connected to a respective control signal bus and are connected via a resistor to one of the terminals of the d.c. voltage source.

Abstract: An electrochromic voltage indicator for detecting the presence and polarity of d.c. voltage, as well as for detecting the presence of a.c. voltage, includes two electrochromic cells, two contact terminals, two capacitors, two resistors and two diodes. First leads of each of the diodes are interconnected and are connected to first leads of each of the resistors and to first leads of each of the electrochromic cells. A second lead of each of the electrochromic cells is electrically connected via a respective capacitor to a second lead of the respective resistor to a second lead of the respective diode and to the respective contact terminal.

Abstract: An electrochrome element control device comprising a voltage source connected in parallel via a switch with a circuit composed of a series-connected electrochrome element and a capacitor for limiting the time the voltage is supplied to the electrochrome element, the charged capacitor supplies voltage of opposite polarity to the electrochrome element upon closure of a second switch connected in parallel to the circuit composed of the electrochrome element and the capacitor. Control of the electrochrome element is considerably simplified therefore.