Measuring Duty Cycle

Making Measurements

Duty cycle (or duty factor) is the percentage of time a signal is above or below a trigger level during one cycle (Figure 8). The duty cycle mode is optimized for measuring the on or off time of logic and switching signals. Systems such as electronic fuel injection systems and switching power supplies are controlled by pulses of varying width, which can be checked by measuring duty cycle.

To measure duty cycle, set up the meter to measure frequency; then press Hz a second time. As with the

frequency function, you can change the slope for the meter’s counter by pressing T.

For 5 V logic signals, use the 4 V dc range. For 12 V switching signals in automobiles, use the 40 V dc range. For sine waves, use the lowest range that does not result in multiple triggering. (Normally, a distortion-free signal can be up to ten times the amplitude of the selected voltage range.)

If a duty cycle reading is unstable, press MIN MAX; then scroll to the AVG (average) display.

+Slope	-Slope
Trigger Point	Trigger Point
30% Above	70% Below
+Slope	-Slope
	100%
	iy3f.eps

Figure 8. Components of Duty Cycle Measurements

80 Series III specifications

The Fluke 80 Series III digital multimeters are renowned for their robust engineering, precision, and versatility, making them a staple in the toolkit of electricians, engineers, and technicians. Launched by Fluke Corporation, a leading manufacturer of electronic test tools, the 80 Series III has set a benchmark in the multimeter industry for its reliability and performance.

One of the standout features of the Fluke 80 Series III is its wide measurement capabilities. The device can accurately measure AC and DC voltage, DC current, resistance, frequency, and capacitance. This comprehensive feature set allows users to tackle a variety of tasks, from simple household electrical checks to complex industrial applications. The meter's high input impedance prevents loading effects on circuits, ensuring accurate readings, especially in sensitive electronic applications.

Fluke's proprietary True-RMS technology is another defining characteristic of the 80 Series III. This technology ensures that the multimeter provides accurate readings for both non-linear loads and distorted waveforms, which are common in many modern electrical systems. This capability is particularly valuable in diagnosing issues in variable frequency drives, inverters, and other electronic systems that do not present traditional sinusoidal waveforms.

Durability is a key factor in the design of the Fluke 80 Series III. The multimeter is housed in a rugged, impact-resistant case that can withstand the rigors of fieldwork. It features a built-in protective holster with a probe holder, enhancing portability while safeguarding the device against drops and bumps. Furthermore, the 80 Series III boasts an IP67 rating for dust and water resistance, ensuring reliable performance in adverse conditions.

User-friendliness is also a significant aspect of the Fluke 80 Series III. The large, easy-to-read display, combined with intuitive controls, allows users to navigate its functions with ease. The multimeter features a backlight, enabling use in dimly lit environments, while the hold function ensures that readings can be captured and displayed even after disconnecting the probes.

In addition to these features, the Fluke 80 Series III offers various models to cater to specific needs, such as the 87V for highly accurate measurements in industrial environments and the 86V for temperature measurements with added thermocouple support. Each model maintains the high standards of quality and performance that Fluke is known for.

In summary, the Fluke 80 Series III digital multimeters combine advanced features, high accuracy, and rugged durability, making them indispensable tools for professionals who require reliable performance in challenging environments. Whether for routine maintenance or complex troubleshooting, the 80 Series III offers everything necessary to meet the demands of today’s electrical tasks.

Fluke 80 Series III user manual Measuring Duty Cycle, Components of Duty Cycle Measurements

Models: 80 Series III

Making Measurements