An optical switch includes: a photothyristor that is switched from an off state to an on state by incident light; a light-emitting element that emits outgoing light when the photothyristor is in the on state; and a tunnel junction layer or a III-V compound layer having metallic conductivity. The tunnel junction layer or the III-V compound layer is disposed between the photothyristor and the light-emitting element.

The invention discloses a standby control circuit and a display device. The standby control circuit includes a standby module, at least one power board, and a transistor switch control module comprising at least one transistor switch whose number is equal to that of the at least one power board, each transistor switch is connected between one power board and a mains supply input terminal, the standby module is configured to generate a trigger signal and send the generated trigger signal to each transistor switch, and each transistor switch is configured to be turned on upon receipt of the trigger signal sent from the standby module so as to connect the power board connected thereto with the mains supply input terminal.

Disclosed is a large-range input circuit for digital signals in the range of extra-low voltage signals of 120 V and in the range of low voltage signals of <1500 V, said input circuit comprising series-connected Zener diodes that are polarized in the reverse direction, each one defining at least one switching threshold in the range of the extra-low voltage signals or in the range of the low voltage signals, and can be selected to be active by not being bridged, wherein a respective auxiliary optocoupler, which can be controlled by a microprocessor, is used to bridge the inactive Zener diode.

An apparatus and a method actuate a frequency converter of an electric machine having a safety function, in particular a safe-torque-off (STO) function. Wherein, by a preferably clocked converter circuit, an electrically isolated output voltage is generated from an input voltage, from which output voltage a control signal is generated for the frequency converter for the operation thereof in accordance with standards and for triggering the safety function. An actuation signal is generated for a semiconductor switch which is periodically connected to the input voltage, and the output voltage is limited when the output voltage exceeds a switching threshold.

A solid state switch may include a plurality of inputs, such as to receive a control signal to cause the solid state relay to selectively deliver power from an AC power source to an electrical load (e.g., a heater, a pump, a lighting source, a motor, etc.). The solid state switch may include at metal-oxide-semiconductor field-effect transistors (MOSFETs) connected in a series opposition arrangement, where a gate of each of the MOSFETs may be electrically connected to a corresponding one of the plurality of inputs. A signal output from the MOSFETs may provide a triggering signal at a gate input of each of a corresponding semiconductor switching device to close the solid state relay to enable power delivery from the AC power source to the electrical load.