Abstract: A power amplifier for delivering large currents as well as high voltages of the order of some hundreds of amperes and 1000 or more volts, notably for MRI. The amplifier is constructed as a multilevel inverter in order to comply with the requirement of high voltages while utilizing transistors capable of withstanding lower voltages only. The amplifier is arranged for soft switching, so that the switching losses at said large currents are limited.

Abstract: A triggering system (1) comprises a trigger device (4) to which a trigger input signal is supplied from an input (2) via parallel signal paths (6, 7, 8). One signal path (6) may be a direct connection, while the other signal paths (7, 8) include frequency division devices (10, 13). The signal paths (6, 7, 8) are selectively switched between the input and the trigger device under the control of frequency-dependent switching devices (16, 21) depending on the frequency of a signal obtained from an input signal at the input (2) of the triggering system. As a result, the useful frequency range of the triggering system (1) is extended up to much higher frequencies than would be determined solely by the bandwidth of the trigger device.

Abstract: A trigger arrangement suitable for use in oscilloscopes which include a cathode-ray tube as a change display device, a trigger output signal (10) is displayed from a trigger input signal (6) after the trigger arrangement is released by a release signal (8). Use is made of a series-combination of three bistable elements (2,4,16). The trigger input signal is applied in parallel to the bistable elements and the trigger output signal is obtained after the output of each bistable element has successively changed its state, a difference occurring between the switching levels of the successive bistable elements when the trigger input signal is applied to the bistable elements via differential amplifiers--assumed to be included in the bistable elements (2,4,16). The first two bistable elements (2,4) form an accurately defined release signal (17) for releasing the third bistable element (16).