Fnirsi S1 Smart Multimeter

Fnirsi S1 is a smart digital multimeter with a large display, suitable for quickly checking voltage, resistance and continuity in the workshop and at home. When switched on, it enters AUTO mode, in which it automatically detects whether there is DC or AC voltage, resistance or a short circuit at the probes. It displays the corresponding value without manually switching functions and ranges. The two-line display with a resolution of 9999 counts has large digits readable even from a distance, and measurements refresh approximately three times per second. For AC voltage, it measures the true effective value (True RMS) in the 50Hz-1kHz range.

It measures both DC and AC voltage up to 1000V with a basic accuracy of ±(0.8% + 3 counts), resistance up to 100MΩ, and continuity with an audible signal below 50Ω. The SEL button switches additional functions: diode test, capacitance up to 10mF, frequency up to 10MHz, and temperature from -20 to 1000°C using the included temperature probe (thermocouple). The NCV button activates non-contact AC voltage detection (“NCV”). When the top of the device is brought close to a conductor, it indicates field strength in three levels and beeps at different frequencies. A second press switches the multimeter to LIVE mode for detecting the live wire in a socket. It also offers measured value hold (HOLD) and a flashlight on the back.

The multimeter does not measure current. A clamp meter or wattmeter is suitable for measuring current draw. In automatic mode, the lowest detectable voltage is 0.75V, so lower voltages may be interpreted by the display as resistance. The resistance, capacitance, frequency and diode inputs are overload-protected up to 250V. The device meets CAT III 1000V overvoltage category requirements.

It is powered by an integrated 3.7V/1000mAh lithium battery. It charges via USB-C (5V/1A) from a charger, power bank or computer, and measurements cannot be taken while charging. The multimeter measures 143x75x19 mm and weighs approximately 130g including the battery.

Important notice: Do not apply voltage higher than 1000V to the inputs. Resistance and continuity may only be measured on a de-energized circuit with discharged capacitors.