A method and device is provided for calibrating a time base signal in a photovoltaic inverter, which has a conversion circuit configured to convert a DC current into an AC current. The method comprises the steps of: receiving a reference signal by a receiving unit from an external reference signal source; determining a deviation between the received reference signal and a time base signal which is generated by a local time signal generator; correcting the generated time base signal to minimize the determined deviation or calculating a correction factor, wherein the calibration unit automatically corrects the time base signal obtained from the time signal generator, even when a reference signal is temporarily unavailable, depending on at least one operating parameter which is stored in a data memory and which is formed by an internal temperature inside the housing of the photovoltaic inverter and/or by a measured supply voltage; and adapting predetermined values for components of the conversion circuit depending on the corrected time base signal or depending on the calculated correction factor.

The invention is a portable preset timer designed for a toddler that can be worn as a watch or clipped on. The timer includes a front and opposed rear face with a plurality of lugs positioned at the outer edge of the timer. The timer also includes a plurality of buttons on the front timer face that are configured to start and stop a timer countdown. Each button is controlled by a lock positioned on the outer perimeter of the lock.

A waterproof timer may used in a stand alone mode or a hanging mode inside a shower or kitchen. The timer has adjustable arms lockable in fixed positions using a ratchet mechanism. Each of the arms has a passage through which a cord may pass to hang the timer from a suction cup or a shower head. The time remaining assumes a numeric display inside a ring of graphic indicia. A battery powered LCD powers the display.

A visual timer includes a back shell, a PCB board, an encoder, a color display screen, an adjusting knob, a knob sleeve and a lens. The PCB board is arranged on the front of the back shell, the encoder is arranged at the bottom of the front of the PCB board, the color display screen is arranged on the front of the PCB board, the adjusting knob is arranged on the front of the encoder, the knob sleeve is arranged on the front of the adjusting knob, and the lens is arranged on the front of the color display screen. The timer has the characteristics of time visualization, low efficacy and convenient time adjustment by the adjusting knob, and the maximum timing range can be switched to 120 minutes and 60 minutes.