A solid state equivalent of a relay includes a pair of time delay circuits having inputs which couple to a pseudo coil terminal. One time delay circuit couples to drive a bilateral switch which simulates the operation of a set of normally closed relay contacts and the other time delay circuit is connected in series with an inverter gate and coupled to drive a second bilateral switch which simulates the operation of a set of normally open relay contacts.
Refrigeration equipment, particularly a household refrigerator or the like, having a heat-insulated refrigeration chamber and a refrigeration unit which can be switched-on intermittently by a temperature-dependent control and the heat exchanger of which, arranged in the refrigeration chamber, can be defrosted between the cooling periods through the supply of thermal energy and/or natural incidence of heat from the environment of the refrigeration equipment, the control being equipped with two sensors, one of which measures the air temperature in the refrigeration chamber and the other, the temperature at the heat exchanger. The sensors have their switching functions coupled by a mutually interlocking electronic circuit in which the switching function activated by the temperature at one sensor must run down completely before the switching function activated at the other sensor is set in motion. Proper defrosting of the heat exchanger is ensured and the temperature in the refrigeration chamber is kept constant independent to a large extent of the ambient temperature.
