The BK Precision 390A digital multimeter (also known as a multitester) is an average-sensing, auto-ranging meter for measuring current, voltage, resistance, capacitance, frequency, and temperature in electrical testing applications. The meter comes with a set of detachable test leads. A K-type thermocouple probe is included for taking temperature measurements. An audible continuity sensor confirms a circuit conducts electricity, and a diode test detects proper functioning of a circuit’s diodes. The LCD shows readings in digits and on a 41-segment bar graph. It displays the present measurement or the highest or lowest reading in a session, for tracking sudden changes in readings. The relative mode stores a reading in memory to use as a zero point for subsequent readings so that multiple readings can be compared. The peak maximum or minimum function records instantaneous peak values for current and voltage. The microamp function identifies current changes in flame detector applications. A hold function keeps a reading on the display, even after the meter has been disconnected. An alarm sounds when the test leads are connected to the wrong jack for the measurement being taken. A USB data port connects the meter to a computer (USB cable and software are included). The unit automatically turns off after 30 minutes of nonuse to conserve battery life, and a low-battery indicator signals when the meter's batteries need to be replaced. The meter's body is made of molded rubber, which helps protect it against damage from falls, impacts, and abrasion.
This average-sensing , or average-responding, meter provides accurate readings when measuring linear loads, such as standard induction motors and incandescent lights, where the current or voltage has an undistorted waveform. When turned on, the meter is in auto-ranging mode and automatically selects the correct operating range for the property being measured. It can be switched to manual-ranging mode, which allows the operator to choose the appropriate operating range. The LCD has a 4,000-count resolution, meaning it can display up to 3,999 units (3-3/4 digits) before the operating range needs to be changed. It meets International Electrotechnical Commission (IEC) safety standard 61010 and is certified for Category III installations up to 1,000V, which covers items used with enclosed building circuit installations (such as service panel parts, branch circuits, and fixed installations that are connected directly to a building's AC power supply).
|Maximum alternating current (AC) input||20 amp|
|Maximum direct current (DC) input||20 amp|
|Maximum AC voltage input||750 volts (V)|
|Maximum DC voltage input||1,000V|
|Maximum resistance detected||40 megaohms|
|Maximum capacitance detected||40 millifarads (mF)|
|Maximum frequency detected||40 megahertz (MHz)|
|Temperature measurement range||-50 to 1300 degrees C (-58 to 2372 degrees F)|
|Power supply||9V battery (one, installed)|
|Standards met||European Conformity (CE) marked; Underwriters Laboratory listed; International Electrotechnical Commission (IEC) safety standard 61010-1|
|Weight||320 g/11.3 oz.|
|Dimensions||198 x 90 x 40 mm/7.8 x 3.5 x 1.57 inches (H x W x D)|
H is height, the vertical distance from the lowest to highest point; W is width, the horizontal distance from left to right; D is depth, the horizontal distance from front to back.
Multitesters (also called multimeters) are electrical test meters that measure multiple properties of an electrical circuit, such as current, voltage, resistance, capacitance, and continuity. Available in handheld or benchtop models, multitesters diagnose electrical problems in electrical equipment, wiring, and power supplies. A variety of probes, clamps, and leads can be used to connect the meter to a circuit or device. Multitesters display information either in analog or digital form. Factors that influence meter choice include the electrical properties to be measured, the anticipated range of results, and the desired level of protection against transient voltages. Safety ratings are based on the International Electrotechnical Commission's (IEC) standards for low-voltage test equipment. IEC 61010 delineates four overvoltage installation categories. In general, a meter with a category IV rating will provide more protection against transient voltages than a meter with a lower category rating.
BK Precision manufactures test and measurement instruments for research and development, production-line testing, and electronic field service applications. The company, founded in 1951, is headquartered in Yorba Linda, CA. It meets International Organization for Standardization (ISO) standard 9001:2008 and is compliant with Restriction of Hazardous Substances (RoHS) and waste electronic and electrical equipment (WEEE) directives.