Nextech QC8055 Instruction Manual

The Nextech QC8055 is a professional-grade digital multimeter with advanced measurement capabilities, including AC/DC voltage, current, resistance, capacitance, frequency, duty cycle, diode test, and continuity check. It features a large backlit LCD display, True RMS measurement, data hold, auto power-off, overload protection, and CAT III 1000V safety rating. Below are key sections for safety, features, installation, setup, operation, and troubleshooting.

Features at a Glance

Key components: Large backlit LCD display, rotary function selector, input jacks, data hold button, range button, relative mode button, and protective holster.

Installation

Unpack and inspect contents. Install batteries and test leads.

1. Install batteries: Open battery compartment, insert 9V battery observing polarity.
2. Attach test leads: Insert black lead into COM jack, red lead into appropriate input jack.
3. Attach holster: Slide protective holster onto meter if not pre-installed.
4. Power on: Rotate function selector to desired measurement function.

WARNING! Ensure meter is turned off and test leads are disconnected before installing batteries. Use only specified battery type.

First-Time Setup

Power on meter; perform initial checks.

1. Display test: All segments should appear briefly on power-up.
2. Battery check: Low battery indicator appears when battery is low.
3. Function selection: Rotate selector to desired measurement type.
4. Auto-range: Meter defaults to auto-range; press RANGE for manual range selection.
5. Backlight: Press and hold SELECT to toggle backlight on/off.

CAUTION! Never apply voltage or current to meter when function selector is set to resistance, diode, or continuity mode.

Specifications

• DC Voltage: 0.1mV to 1000V, ±(0.5%+3)
• AC Voltage (True RMS): 0.1mV to 750V, ±(0.8%+5)
• DC Current: 0.1μA to 10A, ±(1.0%+3)
• AC Current (True RMS): 0.1μA to 10A, ±(1.5%+5)
• Resistance: 0.1Ω to 50MΩ, ±(0.8%+3)
• Capacitance: 0.1nF to 100mF, ±(2.5%+5)
• Frequency: 0.01Hz to 10MHz, ±(0.1%+3)
• Duty Cycle: 0.1% to 99.9%, ±(1.0%+3)
• Display: 6000 count LCD with backlight
• Power: 9V battery
• Safety: CAT III 1000V, CAT IV 600V
• Operating Temp: 0°C to 40°C (32°F to 104°F)

Controls and Settings

Front Panel: Rotary function selector, LCD display, input jacks. Buttons: HOLD, RANGE, REL, SELECT, Hz/%.

Function Selector Positions: OFF, V⎓ (DC voltage), V~ (AC voltage), A⎓ (DC current), A~ (AC current), Ω (resistance), ⎋ (continuity), ▷| (diode), F (capacitance), Hz/% (frequency/duty cycle).

Buttons: HOLD freezes display; RANGE toggles auto/manual ranging; REL sets relative reference; SELECT toggles backlight; Hz/% switches between frequency and duty cycle measurements.

Connecting Test Leads

Always connect black lead to COM jack. Red lead connection depends on measurement type.

1. Voltage/Resistance/Diode/Continuity: Red lead to VΩHz jack.
2. Current up to 400mA: Red lead to μAmA jack.
3. Current 400mA to 10A: Red lead to 10A jack.
4. Capacitance/Frequency: Red lead to VΩHz jack.

Tip: Ensure meter is turned off or set to correct function before connecting test leads to circuit.

Measurement Procedures

Follow proper procedures for accurate and safe measurements.

1. Voltage: Set to V⎓ or V~, connect leads in parallel with circuit.
2. Current: Set to A⎓ or A~, connect leads in series with circuit (power off first).
3. Resistance: Set to Ω, ensure circuit is de-energized, connect across component.
4. Continuity: Set to ⎋, circuit must be de-energized, buzzer sounds for <50Ω.
5. Diode Test: Set to ▷|, red lead to anode, black to cathode; typical forward voltage 0.5-0.8V.
6. Capacitance: Set to F, discharge capacitor first, connect directly to terminals.
7. Frequency: Set to Hz/%, connect to signal source, press Hz/% to toggle if needed.

WARNING! Never exceed maximum input limits. Use proper personal protective equipment when working with hazardous voltages.

Safety Features

Overload Protection: Fused current inputs, high-energy fuse for 10A input. Safety Compliance: Meets IEC 61010-1 CAT III 1000V / CAT IV 600V standards. Input Alert: Warning beep if test leads are in current jacks when selector is set to voltage mode.

Care & Maintenance

Keep meter clean and dry. Use soft cloth with mild detergent if needed. Replace batteries when low battery indicator appears. Replace fuses only with identical type and rating.

CAUTION! Do not use abrasive cleaners or solvents. Store in dry place away from extreme temperatures.

Regulatory Information

Complies with IEC 61010-1 safety standards. CE marked for European market. FCC Part 15 Class B compliant. Copyright © 2025 Nextech Instruments. All trademarks are property of their respective owners. For technical support, visit www.nextechinstruments.com or contact 1-800-555-2837.

Troubleshooting

Reset: Remove battery for 30 seconds to reset microprocessor.

Service: 1-800-555-2837; www.nextechinstruments.com