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Joseph F. Keithley (1915–1999) founded Keithley Instruments in 1946. QSII was the license-plate shorthand for his ambition that the company become known for “Quality, Service, Innovation and Integrity”—not a technical standard or performance guarantee.
Who was Joseph F. Keithley?
Joseph Faber Keithley was an American engineer and entrepreneur. According to IEEE’s biography, he earned a bachelor’s degree from MIT in 1937 and a master’s degree in 1938, then worked at Bell Telephone Laboratories from 1938 to 1940. He later did engineering work at the Naval Ordnance Laboratory and received the U.S. Navy’s Distinguished Civilian Service Award in 1945.
In 1946, he founded Keithley Instruments, a company focused on measuring electrical signals and quantities. His career joined hands-on engineering with building a business around precision measurement.
What does QSII stand for?
QSII stands for Quality, Service, Innovation and Integrity. Tektronix, which now presents the Keithley brand, says Keithley wanted the company to be “famous for Quality, Service, Innovation and Integrity,” and that his car’s license plate read “QSII” (Tektronix, “Keithley: 75 Years at the Forefront of Power Engineering”).
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#1 Best Overall
- VERSATILE FUNCTIONALITY: Measures AC/DC voltage up to 600V, 10A DC current, 2MΩ resistance; additional features include continuity, diode test and battery test
- LEAD-ALERT PROTECTION: LEDs on the meter illuminate to indicate proper test lead placement, enhancing accuracy and safety during measurements
- BACKLIT DISPLAY: LCD shows clear readings in low-light conditions for enhanced visibility
- BATTERY TEST: Battery test mode can be used for checking if batteries are working
- CONVENIENT FEATURES: Test lead holders on the back of the meter, kickstand and optional magnetic hanger (Cat. Nos. 69445 or 69417) for hands-free operation
The phrase is best understood as Keithley’s statement of business values. It does not certify a particular instrument, establish a current product specification, or guarantee performance.
What did Keithley Instruments make?
The company’s first important product was the Phantom Repeater, an amplifier designed to strengthen weak electrical signals. It later became known for instruments such as electrometers, picoammeters and Source Measure Units (SMUs), which can both provide an electrical signal and measure a device’s response.
Rank #2
- Additional Tips - The following incorrect operations may cause the multimeter not to show results: Firstly, the plugs of test leads are not fully inserted or not inserted into the correct sockets. Secondly, the manual rotary switch is not placed in the correct position. In addition, this meter can not test all AC Current and below 100mV AC Voltage. Please check the user manual carefully before measurement.
- Versatile Digital Multimeter - Accurately measures AC/DC Voltage, DC Current, Resistance, and Diode. This Multimeter is a really useful tool for solving industrial and household electrical issues. Suitable for Household Outlets, Fuses, Batteries (including Vehicles), Automotive Circuit Troubleshooting, Charging Systems, Testing electronics in Cars etc.
- Troubleshooting with Accuracy - This Multimeter has a sampling speed of 2 times per second; Built-in a backlight LCD display with 3 ½ digits (1999 count) 0.6”, and high polarity including negative and positive readings.
- Ensures Safety - Double fuse is anti-burn and protects from overloading. The silicone cover can protect the multimeter from failing damage and prevent electric shocks. And low battery indication will be displayed when battery power is low.
- Ease of Use - Support Data Hold and Continuity Buzzer. Includes Convenient feature like LCD Backlit Screen makes it easy to use in dimly light areas. Batteries/Set of Test Leads/User Manual are Included.
Keithley Instruments is now a brand in Tektronix’s portfolio. Its product categories include sourcemeters, multimeters, power supplies and data-acquisition systems for precision electronic measurement. Those categories span different tasks: a multimeter measures electrical quantities, while an SMU combines sourcing and measurement in one instrument. The right equipment depends on the signal range and sensitivity required, whether source-and-measure integration is useful, automation and software needs, and the application—such as semiconductor or materials work, education, or general bench testing. QSII is historical context, not a substitute for comparing specifications and application fit.
Is there a book by Joseph F. Keithley?
Yes. Keithley wrote The Story of Electrical and Magnetic Measurements: From 500 BC to the 1940s, published by Wiley in 1998/1999. Wiley lists ISBN 978-0-7803-1193-0 and a length of 260 pages (Wiley book listing). The historical scope makes it a direct route into the development of measurement science, rather than a manual for modern Keithley instruments.
Rank #3
- Versatile Digital Multimeter - Accurately measures AC/DC Current, AC/DC Voltage, Capacitance, Frequency, Duty Cycle, Resistance, Diode, Continuity and Temperature.
- Thoughtful Design - Support Data Hold, Large LCD Backlit Screen, Auto Shut-off and Kickstand make the process of measurements easier. Professional level is reflected in some features include Auto-Ranging capability, and True RMS for measuring both AC Current and Voltage.
- Suitable For Many Occasions - This Multimeter is a golden partner to help to troubleshoot a variety of automotive and household electrical problems safely and accurately.
- Ensure Safety - Double ceramic fuse is anti-burn and protects from overloading，and it will be more secure and reliable； F400mA/600V and F10A/600V explosion-proof ceramic fuse tubes can protect the multimeter effectively.
- Additional Tips - Please take off the cap before using the test leads. Check the manual for more usage information.
How is Joseph F. Keithley remembered in measurement science?
His legacy is reflected both in the instruments associated with his company and in an award bearing his name. The American Physical Society’s Joseph F. Keithley Award for Advances in Measurement Science recognizes advances in measurement science. APS says the award is endowed by Keithley Instruments and its instrument-and-measurement group, and lists a $5,000 award and current recipients (APS Joseph F. Keithley Award).
Between his early work amplifying weak signals, the company’s later measurement instruments, and an award recognizing advances in the field, Keithley’s name remains connected to the practical and scientific work of measuring electrical phenomena.
Quick Recap
Best Value
- VERSATILE FUNCTIONALITY: Measures AC/DC voltage up to 600V, 10A AC/DC current, 50MΩ resistance; additional features include continuity, temperature, capacitance, frequency/duty cycle and diode test
- LEAD-ALERT PROTECTION: LEDs on the meter illuminate to indicate proper test lead placement, enhancing accuracy and safety during measurements
- BACKLIT DISPLAY: LCD shows clear readings in low-light conditions for enhanced visibility
- ACCURATE MEASUREMENTS: Auto-ranging and True Root Mean Squared (TRMS) technology provides precise and accurate measurements
- CONVENIENT FEATURES: Test lead holders on the back of the meter, kickstand and optional magnetic hanger (Cat. Nos. 69445 or 69417) for hands-free operation
Rank #4
- Accurately Test Full Features: Accurately measures AC/DC voltage, DC current, resistance, continuity test, diode and batteries.
- High Quality & Safety :Our multimeter is designed to safely and accurately troubleshoot a variety of automotive and household electrical problems. Overload Protection on all ranges to ensure long-term service life,Low Battery Indication, Audible continuity sensor checks that the circuit or wires conduct electricity. Double insulation with a good angled stand for hand free use.
- EASY TO USE: 2.7"Large Backlit LCD Display, Data Hold, Easy to Read Large Back-light Screen forvisibility in dimly light areas. Our mutimeter tester is widely used in Car repair, Homeuse, Schools, laboratories, Families and factories, suitable for Car Drivers, Beginners,Professional Electricians, Housewives, Students Use.
- Nice Protective Orange Shell with Stand Built: Our digital multimeter can be hand held or stood using its fold out stand. Removable thick rubber cover is made of kind of non-slip slightly soft plastic that will help with drop protection & minor bumps protection.
- 2 YEARS Quality Guarantee & Included 9V Battery: The compartment lid at the back is easy to remove. Battery/Set of Test Leads/User Manual are Included.They guarantee against faulty materials and workmanship for 2 years-giving you total peace of mind. If there is any issue within24 months of your purchase, we will replace it for vou with no doubt.
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