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Machine Vibration Activates Hour Meter:
01/16/97 EDN-Design Ideas by David Johnson Battery-powered digital
hour meters commonly monitor how long a machine is in operation by
detecting when the machine is supplied with power. However, it is often
difficult or dangerous to connect a battery-powered hour meter to a
line-powered machine. When the machine being monitored produces de-tectable
vibrations, you can use the circuit in Figure 1, which doesn't require
any power-line connections. The circuit uses just one IC and allows you
to turn a battery-powered hour meter on and off according to a machine's
vibration. (added 09/05) |
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Magnetometer: (schematic
added 8/03) |
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Make a Low Cost Benchtop Power Meter:
09/11/98 EDN-Design Ideas / (added 6/06) |
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Make Your Own Shunts: Using a modern
multimeter to measure current can sometimes be difficult. Many of
these meters will only measure up to one amp. However, may
112-volt DC powered projects draw a lot more than that. If you have ever
thought of purchasing a commercial shunt to solve the problem, your know
just how expensive they can be. Commercial shunts, while very
precise, frequently cost more than the projects they are measuring!
However, there is a better and cheaper alternative that will work
perfectly well in most situations... (added 2/06) |
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Making Differential Probes: For sensing
audio signal voltages across devices that are not ground referenced
(added 6/03) |
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MAR/RAM Test Fixture Instructions AN-60-018:
Application Note MiniCircuits.com (app note added 6/06) |
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MAV Test Fixture Instructions AN-60-025:
Application Note MiniCircuits.com (app note added 6/06) |
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Measure humidity and temperature on one TTL line:
08/30/01 EDN Design Ideas / (added 1/05) By combining
the responses of an Analog Devices (www.analog.com) AD590 temperature
sensor and a Humirel (www.humirel.com) HS1101 humidity sensor, you can
generate a single TTL-level signal containing information from both
sensors (Figure 1). This design uses a 74HC123 monostable multivibrator,
IC1, to form a free-running oscillator. ... |
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Measure open circuited cables using a multimeter:
09/26/02 EDN Design Ideas / (added 1/05) You can use a
multimeter with capacitance-measurement capability to measure the length
of wire or cable to an open circuit. The capacitance of a pair of wires
(or a wire to a shield) is directly proportional to the length of the
wire. If you know the capacitance per foot of wire, then you can
calculate how far it is to the open circuit.... |
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Measure temperature in remote locations:
10/12/00 EDN-Design Ideas / (added 6/06)
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Measurement methods: Application Note
MiniCircuits.com (app note added 6/06) |
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Measuring AC Frequency using Pulse Width Measurement Mode:
Toshiba 870X Series Application Note (app note added 2/06) |
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Measuring Jitter in Digital Systems (AN 1448-1):
Agilent Application Note (added 6/06) |
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Measuring RF Voltages with a VOM:
(schematic added 8/03) |
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Measuring self resonant frequency:
Coilcraft RF Magnetics Application Notes -(added 6/06) |
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Measuring sensitivity of transponder coils:
Coilcraft RF Magnetics Application Notes -(added 6/06) |
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Method simplifies testing high Q devices:
02/21/02 EDN Design Ideas / (added 1/05) The design of
low-phase-noise oscillators requires careful attention to resonator
unloaded Q. In the construction of a low-phase-noise, high-frequency
oscillator, the goal is to achieve an unloaded-Q figure greater than 400
in a reasonable package. Also, you need to monitor the effect of the
package and pc-board arrangement. ... |
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Method Tests Cables:
10/17/02 EDN Design Ideas / (added 1/05) Engineers
have long known how to test a cable for continuity by simply connecting
all conductors in series and checking with an ohmmeter. This method is
sometimes impractical, however, because it cannot check for short
circuits. The method shown in Figure 1 solves the short-circuit problem.
Connecting LED indicators at each shorting loop provides a visual
indication.... |
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Microphone Circuit Test Oscillator:
440 Hz Tone generator for testing XLR microph1-lines (added 5/02) |
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Microphone Polarity Tester:
(electronic schematic / circuit added 4/02) |
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MIDI interface/cable tester: (circuit /
schematic added 6/05) |
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MIDITester: (circuit /
schematic design added 6/06) |
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MilliGauss Meter: (electronic design
added 9/02) |
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Mini DDS (direct Digital Synthesizer):
(schematic added 8/03) |
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Mini DDS Synth: (project / circuit added
10/06) |
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Missing Codes Tester Checks 16 Bit ADC in 7 Sec:
06/10/99 EDN-Design Ideas / (added 6/06) As the resolution of ADCs
increases from 12 to 16 bits and higher, the difficulty in testing the "nomissing-codes
"specification grows proportionately. To fully guarantee no missing
codes for a 16-bit ADC requires testing all 2 16-1 possible output... |
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Mixed Signal Testing using the IEEE 1149.4 STA400:
National Semiconductor Application Note (app note added
2/06) |
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Modified Scope Probe Tests Surface Mount Assemblies:
09/25/97 EDN-Design Ideas / (added 3/03) |
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Monitoring Additional Supplies with the ADM1062-ADM1069 Super
Sequencers™: AN-781 Analog Devices
Application Note (app note added 6/06) |
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Monitoring High Voltages with the ADM1062-ADM1069 Super Sequencers™:
AN-782 Analog Devices Application Note (app note added 6/06) |
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Monitoring Negative Voltages with the ADM1062-ADM1069 Super Sequencers™:
AN-780 Analog Devices Application Note (app note added 6/06) |
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Morse Monitor: (circuit /
schematic design added 6/06) |
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MOSFET Tester: This
testing procedure is for use with a digital multimeter in the diode
test-range with a minimum of 3.3 volt over d.u.t. (diode-under-test).
If your multi-meter is less than that it will not do the test.
Check your meter manual for the specs. (added 2/06) |
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Moving coil meter measures Low level Currents:
03/03/05 EDN Design Ideas / (added 5/05) Although an analog
moving-coil meter may lack the resolution and accuracy that a digital
readout provides, a meter remains the display of choice for certain
applications. A digital readout simply cannot provide information about
a measurement's rate of change, and tracking a reading's trend is easier
on an analog meter. |
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MPU temperature meter #2: Multi point
diode temperature meter to replace thermister temperture meter. This is
for diode temperture sensors icludes on-die thermal diode of
micro-processor. (added 6/06) |
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MPU temperature meter: Multi point
temperature meter which displays tempertures to an LED display with time
divided. This is good for monitoring temperature of PC components.
(added 6/06) |
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Multi Wire Cable Tester:
(electronic schematic / circuit added 4/02) |
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Nitrogen Spark Generator:
(circuit / schematic added 6/05) |
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Noncontact Devicetests power supplies:
03/01/01 EDN-Design Ideas / (added 2/06)
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NTSC Test Signal Generator: An
accurate test signal generator for television calibration and
measurements. (added 6/06) |
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Off Line Telephone Tester: Here is a
circuit of an off-line Telephone tester which does not require any
Telephone line for testing a Telephone instrument. The circuit is so
simple that it can be easily assembled even by a novice having very
little knowledge of electronics. (added 5/02) |
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Opacity Meter: File contains several
circuits, scroll to find this one (added 2/05) |
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OpAmp Design and Test Board:
(electronic schematic / circuit added 4/02) |
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Optimizing Bluetooth DeviceBattery Drain Measurements in Manufacturing
(5988-6064EN):
Agilent Application Note 1396 (added 4/08) |
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Owens Bridge Inductance Measurement Device:
The circuit is a very simple RCRCRC filtered supply and a current
source. The filtered supply provides 174 bolts at no load, and drops to
106 volts at 400mA. Ripple must be relatively low. In this supply,
ripple is about 2 mV at 400mA load, so it is sufficiently filtered.
Available voltage ranges from 154 volts at 100mA to 136 volts at 200mA
to 106 volts at 400mA. The current source consists of a single IRF730
with a degeneration resistor in series with the source. About 14 volts
maximum is placed on the gate, and with 4 volts gate-to-source voltage,
a 100 ohm resistor in the source will develop 100mA. That resistor is
range switched . 100 ohms is used for the Lx10 range, allowing 100mA
maximum on that range, but an additional 100 ohm resistor is paralleled
for the Lx1 range to allow 200mA, and an additional 50 ohms is
paralleled on the Lx0.1 range for higher current. ... (added 8/03) |