Product Aug. 23, 2016

Hioki Launches Digital Multimeter DT4223 and DT4224

Instruments Reverse the Conventional Wisdom Regarding Tester Safety with Voltage Input Protection Functionality

August 20, 2016 - Nagano, Japan

Hioki is pleased to announce the launch of the Digital Multimeter DT4223 and DT4224.  The new products were developed as multimeters that would enable professionals to do their jobs quickly without causing power outages.

Caution is necessary when using testers to measure high voltages. Improperly setting the instrument to its resistance range, for example, when measuring a high voltage can cause a power outage by tripping a circuit breaker or result in an electrical accident, for example by producing sparks that can cause burns.  By providing the world’s first voltage input protection function, the new DT4223 and DT4224 dramatically improve safety, preventing electrical accidents caused by operator mistakes and enabling greater peace of mind than is possible with previous products.

The new instruments also offer a number of other improvements over legacy models, including a broader range of operating temperatures and an auto-hold function that makes it easier to read measured values.  The DT4223 provides measurement functions designed for use in electrical work, including automatic AC/DC detection functionality for use during voltage measurement and voltage detection functionality, while the DT4224 can be used in a broad range of applications thanks to functionality such as capacitance and diode measurement.

Principal Applications
Maintenance inspections of buildings, plant equipment, elevators, and other systems
R&D and maintenance inspections of inverters, solar power systems, fuel cells, and electric vehicles

Product Features
1. World’s first voltage input protection function
Selecting the continuity check, resistance, capacitance, or diode measurement range on a conventional tester places the instrument in a low-impedance state. If a high voltage is input to the tester while in this state, the oversight can cause a power outage by tripping a circuit breaker or result in an electrical accident, for example by producing sparks that can cause burns at the tips of its test leads.
The DT4223 and DT4224 maintain an input impedance on par with that used for voltage measurement when set to the continuity check, resistance, capacitance, or diode measurement range, eliminating the risk of the above electrical accidents even if a high voltage is applied to the tester.

This voltage input protection function was made possible by a design that automatically detects what has been connected to the instrument via the test leads. If a component such as a resistor is connected, the tester switches to a lower input impedance and performs the measurement. The function, which is the first of its kind in the world, ensures safety by switching back to a higher input impedance the moment the test leads are removed from the resistance.

2. Visual and aural warnings of improper operation
If the operator mistakenly inputs a voltage while the instrument is set to its continuity check, resistance, capacitance, or diode measurement range, the screen will flash red and the tester will beep in order to immediately warn the user of the error.

3. Expanded operating temperature range of -10°C to 65°C and improved durability
The DT4223 and DT4224 expand the operating temperature range of previous products to -10°C to 65°C (versus -10°C to 50°C for the DT4221 and DT4222) to allow use under conditions of intense heat.

4. Auto-hold function
This function automatically holds the measured value on the screen once it stabilizes while the operator is holding the two test leads with both hands, enabling the operator to check the value once his or her hands are free. An optional magnetic strap allows measurement to be performed even more efficiently.


Established in 1935, HIOKI E.E. CORPORATION (TSE: 6866) has grown to become a world leader in providing consistent delivery of test and measuring  instruments through advanced design, manufacturing, and sales and services. By offering over 200 main products characterized by safety andquality while meeting an expansive range of applications, we aim to contribute to the efficiency and value of our customers' work in research and development, production and electrical maintenance. HIOKI products and services are available around the world through our extensive network of subsidiaries and distributors. Information about HIOKI is available at

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Hioki DT4223 Digital Multimeter

Hioki DT4224 Digital Multimeter