Controllable release switch for an electrical circuit breaker, the circuit breaker being switchable between an open state and a closed state, this release switch comprising: - an actuator comprising a coupling element which is displaceable between an inoperative position and a released position, the coupling element being intended to be coupled mechanically to a switching mechanism of an electrical circuit breaker in order to cause the switching of the circuit breaker from a closed state towards an open state when the coupling element passes from the inoperative position towards the released position, and - a control device, configured in order to supply the actuator, in response to receipt, by the release switch, of a release control signal (Vcmd), in order to displace the coupling element from the inoperative position towards the released position; the actuator being a magnetic actuator comprising a coil, configured in order to displace the coupling element from the inoperative position towards the released position when it is supplied with an electrical current pulse of intensity greater than a first predefined threshold (I-min) for a duration greater than or equal to a predefined duration (T-on), the release switch being characterised in that the control device is configured in order to supply electrically the coil, upon receipt of the control signal (Vcmd) and as long as the control signal (Vcmd) is maintained, with a series of electrical current pulses of duration equal to the predefined duration (T-on) and of intensity greater than or equal to the first threshold (I-min) and less than or equal to a second threshold (I-max), this second threshold (I-max) being at most equal to 120% of the first threshold (I-min); in that the control signal (Vcmd) is an electrical voltage, received at an input of the release switch, the control device being adapted in order to be supplied electrically by the control signal (Vcmd), in that the control device comprises: - a regulated, current-limited voltage source, connected in series with the coil between the input and an electrical earth of the control device, this regulated, current-limited voltage source being configured in order to deliver a supply voltage (Vcc) on a supply rail as long as it is supplied by the control signal (Vcmd), - an excitation module, configured in order to be supplied electrically by the supply voltage (Vcc) and in order to control the generation of the electric current pulses, the regulated, current-limited voltage source being, furthermore, configured in order to inject selectively into the coil an electrical current of intensity equal to the second predetermined threshold (I-max) and, alternately, to interrupt the circulation of this electrical current, in response to release and interruption orders generated by the excitation module; in that the control device comprises a probe for measuring the current which circulates through the coil, and in that the excitation module is programmed in order, successively, to activate then inhibit the injection of the electrical current by the regulated, current-limited voltage source, in order to generate each electrical current pulse, the excitation module being programmed in order to control this inhibition at the end of the predetermined delay (T-on), this delay being counted by the excitation module from the moment when the current measured by the measuring probe exceeds the first threshold value (I-min). - an actuator comprising a coupling element which is displaceable between an inoperative position and a released position, the coupling element being intended to be coupled mechanically to a switching mechanism of an electrical circuit breaker in order to cause the switching of the circuit breaker from a closed state towards an open state when the coupling element passes from the inoperative position towards the released position, and - a control device, configured in order to supply the actuator, in response to receipt, by the release switch, of a release control signal (Vcmd), in order to displace the coupling element from the inoperative position towards the released position; - a regulated, current-limited voltage source, connected in series with the coil between the input and an electrical earth of the control device, this regulated, current-limited voltage source being configured in order to deliver a supply voltage (Vcc) on a supply rail as long as it is supplied by the control signal (Vcmd), - an excitation module, configured in order to be supplied electrically by the supply voltage (Vcc) and in order to control the generation of the electric current pulses,