Abstract: A multimeter has a protection mechanism of charging. A measuring body includes a shell and a knob-turning set, and the shell has a charging socket. A control module is disposed in the shell and includes a circuit board and a connector electrically connected with the circuit board. The connector is disposed corresponding to the charging socket, and the circuit board is electrically connected with the knob-turning set and selectively actuated through a rotation of the knob-turning set. A charging unit is disposed in the shell and electrically connected with the connector. A stopper moves with the knob-turning set together. An external plug is inserted with the connector via the charging socket, and the stopper is actuated so that the knob-turning set will not to be rotated. Thus, it ensures the multimeter cannot perform a measurement when it is charging for avoiding danger.

Abstract: An electric meter apparatus with a light-blinking function includes a positive-side probe, a negative-side probe, a resistor measuring circuit, a voltage supply unit, a micro control unit and a light-blinking indication unit. The resistor measuring circuit is configured to measure an external resistor to obtain a resistance value of the external resistor through the positive-side probe and the negative-side probe. The resistor measuring circuit is configured to inform the micro control unit of the resistance value of the external resistor. If the resistance value of the external resistor is less than or equal to a predetermined value, the micro control unit is configured to control the light-blinking indication unit to light, to be turned off or to light blinkingly, in order to remind the user.

Abstract: A meter apparatus having three-phase judgment function includes a control unit, a multimeter measurement unit electrically connected to the control unit, a three-phase judgment unit electrically connected to the control unit, a first measurement jack electrically connected to the multimeter measurement unit and the three-phase judgment unit, a second measurement jack electrically connected to the multimeter measurement unit and the three-phase judgment unit, and a third measurement jack electrically connected to the multimeter measurement unit and the three-phase judgment unit.

Abstract: A clamp meter with multipoint measurement includes a current-measuring unit, an analog-to-digital converting unit, and a measuring-position judgment unit. The current-measuring unit includes a plurality of current-measuring positions calibrated according to the measuring-position judgment unit. The current-measuring unit measures the current of the current-measuring position judged by the measuring-position judgment unit.

Abstract: A multimeter with filtered measurement mode is disclosed. The multimeter includes a signal conditioning circuit, a low-pass filter, a microprocessor, a measurement circuit, a root-mean-square (RMS) converter, a display unit, and an external rotary switch. The signal conditioning circuit receives a control signal to select an operation mode of the multimeter. The low-pass filter is electrically connected to the signal conditioning circuit. The microprocessor is electrically connected to the signal conditioning circuit. The measurement circuit is electrically connected to the microprocessor and the RMS converter to measure a signal outputted from the RMS converter. The display unit is electrically connected to the microprocessor and the measurement circuit. Also, the external rotary switch is optionally connected to the microprocessor. Whereby rotating the external rotary switch to generate the control signal and perform a low-pass filtering mode to communicate the low-pass filter with the RMS converter.

Abstract: A measuring apparatus for capacitor is applied to a charging power source and a capacitor to be measured. The measuring apparatus for capacitor includes a microcontroller unit, an analog-digital converter unit, a charging-side switch unit, a charging-side resistor unit, a discharging-side switch unit and a discharging-side resistor unit. The capacitor to be measured is charged and discharged by the charging-side switch unit and the discharging-side switch unit controlled by the microcontroller unit. The charging and discharging voltage and time variation of the capacitor to be measured are measured by the analog-digital converter unit to calculate the capacitance value of the capacitor to be measured.

Abstract: An electric meter having a detachable measuring bar includes a main body, a first measuring bar and a second measuring bar assembly. One end of the main body is formed with a supporting portion. The first measuring bar has a connecting portion and a probe formed at the other end of the connecting portion. The connecting portion is detachably connected with the supporting portion of the main body. The second measuring bar assembly comprises a second measuring bar and a lead. Both ends of the lead are connected to the main body and the second measuring bar. Via this arrangement, when the first measuring bar is worn or damaged in use, the first measuring bar can be replaced, thereby reducing the purchasing cost of the electric meter.

Abstract: A detecting device for fuel injecting interval is provided, more particularly, to a portable and digital detecting device for detecting the fuel injecting interval of the injector of engine. The detecting device comprises a level transformer, a signal delay filter, a digital signal processor, and a display. The input of the level transformer 2 is electrical connected to the output load terminal of the controller 1 of the injector of engine in a way of inverse measure. The high frequency noise in the target waveform is filtered by the signal delay filter. The delay time within the detecting device is calculated by the digital signal processor and is subtracted. The resulted and exact fuel injecting interval is illustrated in the display. The detecting device features a compact configuration, easy to maintain and low service cost. Most important, the detecting device features a lower measuring error level.