Abstract: The invention relates to a control circuit for a semi-conductor power element, comprising a circuit generating a signal synchronous with the variable current supply signal of the semi-conductor power element, and a logic circuit with high input impedance to receive directly, on the one hand, the said synchronous signal and, on the other hand, the low strength detection signal and which is such that the delay circuit is combined to the high input impedance logic circuit to prevent the production of control pulses on the electrode controlling the semi-conductor or power element, if one of the components of the control circuit should become faulty.The invention finds an application in burner control and safety devices.

Abstract: A fail-safe control circuit for supplying the electrical power for operating a safety stop member, such as an electromagnetic valve, in response to low power information, wherein any failure of a component causes the safety stop member to close.The energy taken from the alternative current supply network by the periodic charging of a capacitor is transmitted to a load by the energizing of a thyristor. The spontaneous energizing of the thyristor causes the appearance of an overcurrent disabling the device.Applications to combustion, premises, medical monitoring devices.

Abstract: A piezoelectric lighter for gas appliances, comprises a piezoelectric module adapted to be struck at one end. A case of insulating material contains the module of which the end opposite that receiving the impact is connected to an electrode emerging from the case. A hammer lever, also of insulating material, bears a percussion hammer, and pivots around an axle of the case on being subjected to the action of a spring. Electrical continuity is provided between the struck end and the metallic mass of the appliance on which the lighter is mounted.

Abstract: The device comprises flame detection means and a generating circuit adapted to deliver a signal when a flame signal, generated by the flame detection means, is applied to one of its inputs. The generating circuit is arranged so as to be unable to deliver an actuating signal in the case of failure of one of its elements, even if a flame signal is applied to said input. The circuit comprises oscillator means including a triggering input adapted to receive a triggering signal of low value and means for applying the flame signal to said triggering input. The oscillator means is arranged to generate a periodic signal of substantially constant peak to peak amplitude and of value substantially higher than that of the triggering signal, when a signal appears on said triggering input having a value between pre-determined limits.

Abstract: The invention relates to systems comprising a triggering element such as a thyristor triggered from a relaxation oscillator and relates more particularly to an electrical igniter.In this system means are provided for ensuring the automatic decrease of the intensity of the triggering pulses supplied by the oscillator so that triggering automatically stops after a predetermined time. These means comprise a timing mechanism formed by a resistance inserted in series in the discharge circuit of the oscillator with a capacitor and diode in parallel on the said resistance, the diode being oriented so as to charge the capacitor under the action of pulses supplied by the oscillator.The invention can be applied to an igniter for gas burners.