U.S. Navy
TV-3/U Tube Tester manual - . . .
UJT Test - This testing procedure is for use with a digital multimeter in the OHM's test-range. The UJT
is a solid-state 3-terminal (TO-18 case) emiconductor. UJT's are used in pulse/timing, oscillator, sensing, and
thyristor triggering circuits. The most common one being probably the 2N2646 from Motorola. . . . [Tony van
Roon's circuit]
UL Ground Resistance Tester - UL requires that an electrical system using a metal chassis earth ground connection have a
resistance of less than 0. 1 ohms. This resistance must be tested with actual line current in excess or 10 Amps.
The circuit shown uses a couple of LEDs to indicate if in fact the resistance is less than 0. 1 ohms - modified
on July 10, 2006 . . . [Circuit by Dave Johnson P.E., 04/28/01]
Ultra High Sensitive Probe - This circuit is so sensitive it will detect mains hum. Simply move it across any wall and it
will detect where the mains cable is located. It has a gain of about 200 × 200 × 200 = 8, 000, 000 and will also
detect. . . [Izhar Fareed-Circuit Designer]
Ultra Low
Power detects Clear Fluid - Using an ultra low power
technique, this circuit detects when a clear fluid is inside a piece of clear plastic tubing. It can be used for
fluid level control and monitoring . . . [Hobby Circuit designed by David Johnson P.E., 10/22/05]
Ultra Low Power
Human Finger Detector - The circuit below seems to
work well and averages a current drain of only 10 microamps from a lithium cell. It uses a single CA4013 dual D
flip/flop. One section is wired as a pulse generator. It applies 10us 10ma pulses to a LED inside a slotted
optical sensor at a rate of about 50Hz. The phototransistor in the second half of the sensor detects the pulses
and sends a pulse to the data input of the second flip/flop in the 4013 package. If there is nothing between the
LED and the phototransistor, the inverting output of the 4013 remains low. . . . [Circuit Solution by Dave
Johnson P.E., 05/02/06]
Ultra Low Power LCD Indicator - This circuit serves as an ultra-low power replacement for multiple LED on-off indicators. It
also has the advantage of being easy to read in full daylight. With the parts shown, it is possible to display
four bits of information. . . . [G. Forrest Cook]
Ultraprecise Current Sensing with LTC6102 - Very low input offset allows using low value resistors while maintaining high measurement
resolution. Using low value also reduces power losses and temperature rise. . . . [Linear Technology App Note - ,
Jul 2, 2012]
Ultra-simple Voltage Probe - . . . [Designer's name not included]
Ultrasonic Range Meter - On these pages, I will introduce the Ultrasonic Range Meter with PIC16F873.As for the range
meter which doesn't use PIC, refer to "Ultrasonic Range Meter". I created the PCB pattern for this circuit using
EAGLE CAD. With this circuit, the following features of PIC16F873 are used. . . . [Seiichi Inoue's Web Site]
Under/Over Voltage
Alarm on AC Line - Power lines, which deviate much
beyond normal voltages can damage expensive electronic equipment. The circuit below sounds an alarm whenever the
line voltage is higher or lower than normal. I set the alarm limits at about +-15% from standard levels . . .
[Circuit by Dave Johnson P.E., 03/29/09]
Understanding and selecting RMS voltmeters - 05/11/00 EDN Technical Article: Failing to verify ac-voltmeter accuracy before conducting
rms-noise measurements may cause highly misleading results. . . [by Jim Williams and Todd Owen, Jim Williams,
EDN's most revered contributor-At 63 years of age, Williams passed away in June 2011 after a stroke.]
Universal frequency counter &
voltage meter - . . . [by Aleksander Stare]
Universal IR Remote Control Tester - This tester consists of two integrated remote control receivers whose outputs drive an LED
to indicate when a suitable infrared signal is received. To cover all current infrared remote controls, one
receiver (the TSOP1736) has maximum sensitivity to carriers at 36 kHz, the other (the TSOP1738) to carriers at 38
kHzmust register on this site. . . [Published in Elecktor July/Aug, 2010]
Unplugged Power Cord Alarm - Many medical devices, such a portable X-ray and ultrasound equipment, carry their own
batteries. However, the frantic pace of some hospital emergency rooms might cause the device to be shoved off
into a corner without being plugged back into an AC power source to recharge their batteries. So, I designed this
circuit to emit an audible alarm whenever the device’s power cord was unplugged from the wall for a period of
time . . . [Circuit by David Johnson P.E., 07/08/00]
Unusual clock with
AT89C2051 - . . . [by IQ Technologies Industry, unless
otherwise noted online]
Use a heated
diode as a Flow sensor - 12/23/13 EDN Design Idea A hot
diode senses air or fluid flow. . . [by Raju Baddi
Use a PC's parallel port to program a clock source - 12/07/04 EDN Design Idea This Design Idea shows how you can use Linear Technology's
LTC6903 programmable oscillator as a clock source for direct-digital synthesis, data conversion,
switched-capacitor filtering, clock, and voltage-controlled oscillator circuit. . . [by William Grill, Honeywell
BRGA, Lenexa, KS]
Use a switching-regulator controller to generate fast pulses - 04/13/06 EDN Design Idea Switching-regulator-controller ICs can deliver gate-drive
pulses with rise and fall times of less than 2 nsec, making them ideal candidates for laboratory
pulse-generators. . . [by Mitchell Lee, Linear Technology Corp]
Use A Transistor and An Ammeter to Measure Inductance - 04/05/12 EDN Design Idea Bipolar junction transistors transfer a current from a
lower-resistance emitter to a higher-resistance collector. You can use this property to measure inductance. . .
[by Raju Baddi, Tata Institute of Fundamental Research, Pune, India]
Use Air-Core-Coil Resistance to Estimate Inductance - 01/05/12 EDN Design Idea If the coil is tightly wound you do not need the number of
turns to calculate inductance. This Design Idea shows how to calculate the inductance of a multilayer air-core
coil using only its dimensions and resistance. If you know the dimensions and the number of turns on an air-core
coil, you can easily calculate the inductance. With the dimensions in millimeters, the inductance, L, in
microhenries is a function of the square of the turns, as the following equation shows: L=0.
008×D2×N2/(3D+9h+10g), where D is the average diameter of the coil; h is the height of the coil; and g is the
depth of the coil—all in millimeters (Figure 1). . . [by Peter Demchenko, Vilnius, Lithuania]
Use
op-amp injection for Bode analysis - 09/16/04 EDN Design
Idea Bode analysis is an excellent way to measure small-signal stability and loop response in power-supply
designs. Bode analysis monitors gain and phase of a control loop. It performs this monitoring by breaking the
feedback loop and. . . [by Martin Galinski, Micrel Semiconductor, San Jose, CA]
Use
RS-232C port to measure pressure - 08/01/97 EDN Design
Idea A simple circuit and accompanying software turn a pressure sensor into an accurate and cheap pressure
digitizer that works with any PC's RS-232C COM port. Many manufacturers make micromachined silicon piezoresistive
pressure sensors. . . [by W Stephen Woodward, University of North Carolina--Chapel Hill]
Use Your Personal
Computer for Measurement and Control - Scroll to find this
circuit. . . [Analog Devices-Analog Dialogue by Mills, John]
Use your printer port as a high-current ammeter - 07/06/00 EDN Design Idea With a few inexpensive components and INT1Ch, you can turn the
printer port of your PC into a high-current ammeter. . . [by K Suresh, Indira Gandhi Centre for Atomic Research,
Kalpakkam, India]
Using Histogram
Techniques to Measure A/D Converter Noise - Analog
Devices-Analog Dialogue. . . [by Ruscak, Steve and Singer, Larry]
Using Vector Modulation
Analysis in the Integration, troubleshooting & Design of Digital RF Communications Systems - Application Note. . . [Aligent]
UTP Cable Tester - . . .
V/I Curve Tracer - The V/I Curve Tracer is an indispensable tool for troubleshooting circuits and testing
components. The circuit traces the current versus voltage curve for the component under test on an ordinary
oscilloscope. The peak-to-peak test voltage. . . [Copyright © 1998 Wenzel Associates, Inc.]
Vacuum Tube Grid Leak
Detector: Needs an Amplifier - . . .
Vacuum Tube Plate
Detector: Needs an Amplifier - . . .
VCR head
amplifier tester - . . .
VCR Tuner Based RF Spectrum Analyzer
Schematic - . . .
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