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Battery Low Voltage Beeper - This circuit provides an audible and visual low
voltage warning for 12V battery powered devices. Idle current: 6ma Low Voltage Warning
current: 15ma…. [Circuit designed by Forrest Cook] |
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Battery Tester for 1.5 & 9V - Schematic & Notes only, no description
included…. [Martthew B's circuit] |
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Bearing Runout Measurements - Aligent App Note (app note added 6/07)
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Beat Balance Metal Detector - A Beat Balance Metal Detector made from
discrete components. [b:8451936e31]Notes:[/b:8451936e31] Various embodiments of the BB
metal detector have been published, and it has been widely described in the press as a
new genre. Instead of using a search and a reference oscillator as with BFO, or Tx and
Rx coils as with IB, it uses two transmitters or search oscillators with IB-style coil
overlap. The frequencies of the two oscillators are then mixed in similar fashion to
BFO, to produce an audible heterodyne. On the surface of it, this design would seem to
represent little more than a.... |
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Beeper to find short circuits - (schematic added 09/08) [Site is under
construction right now] |
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Bench Amplifier - (electronic design added 6/07) |
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BER Meter is Easy to Build - 03/02/00 EDN-Design Ideas....A bit-error-rate (BER]tester
is a basic tool for digital-communications measurements. Although many commercial BER
testers are available, you can easily design and build an inexpensive version. The
scheme in Figure 1 has performance similar to that of a.... [Design Idea by Luis
Miguel Brugarolas, Sire Sistemas y Redes Telmaticas, Tres Cantos, Madrid, Spain] |
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BJT Tester - A test circuit for BJT (Bipolar Junction Transistors).
This circuit can measure both small signal hfe and DC current gain hFE of a low
to medium power power transistor. In addition it can measure collector-base and
collector-emitter leakage current. This circuit can also measure hFE at
different operating points. A multimeter can be used at multiple test sockets to make
all measurements, or two DC ammeters can be used.... [Circuit design by Andy Collison] |
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Blood Glucose Monitor - Intersil Application Block Diagram....[App Note]
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Bluetooth RF Measurement Fundamentals: Application Note 1333-1 - Agilent
Application Note....[App Note] |
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Boole helps simplify wiring and save money - 8-Jul-04 Issue of EDN To
safely observe the positions of two cylinders, you need two signals one circuit,
X, which is open only when both cylinders are in a safe position (two normally closed
switches in parallel], and one circuit, Y, which is closed only when both cylinders
are in a safe position (two normally open switches in series, Figure 1].... [Design
Idea by Jean-Bernard Guiot, Mulhouse, France] |
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Boosting Regulator Current - An outboard pass transistor used to increase
the current output of a voltage regulator IC…. [dircuit design by Andy Collison] |
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Broad Band 2MHz Optical Fiber Receiver - If you need more sensitivity than
the above circuit this circuit provides about ten times more gain. It too is designed
around an inexpensive plastic optical fiber detector.... [Designed by David A.
Johnson] |
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Broad Band 50mhz Optical Fiber Receiver Version A - If the above circuit it
still too slow, you can try this circuit. What it lacks in sensitivity it makes up for
in speed. The circuit attaches a plastic fiber optic PIN photodiode assembly to a
small box containing a small 3v battery and a standard BNC plug. When the box is
plugged into to the input of an oscilloscope with a 50-ohm termination resistor, it
can detect light pulse frequencies beyond 100MHz.... [Designed by David A. Johnson] |
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Broad Band 5mhz Optical Fiber Receiver - This circuit is a simple broad band
light detector that uses a very inexpensive IC and a PIN photodiode that is packaged
for use with plastic optical fibers. It has a bandwidth from 1KHz to over 5MHz. It is
great for experimenting with various modulated light sources.... [Designed by David A.
Johnson] |
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Broken coil detector is simple yet robust - 4-Mar-10 Issue of EDN An
oscillator, filters, and comparators detect missing wires in an assembly line....
[Design Idea by Juan Pablo Caram, Santiago, Chile] |
| Brownout Voltage Tester - I used this circuit
years ago to test AC line powered devices under 95vac line voltage conditions.
It has a rating of 250 watts. …. [Hobby Corner Circuit by Dave Johnson] |
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Brüel & Kjaer 2409/2416 VTVM schematic - (added 07/07/07) |
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Build a Magnetic Field Immunity Tester - You can assemble a precompliance
(or even full compliance) magnetic field immunity test system in a few hours using
common laboratory instruments, a 100-W audio amplifier, some white PVC “Schedule-40”
3/4-in. water pipe, some wood, and a copper or aluminum sheet....(Circuit design added
08/08/08) |
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Build a USB-based GPIB controller - 16-Dec-05 Issue of EDN
Roll-your-own USB-based instrumentation bus.... [Design Idea by Boštjan Glazar, Marko
Jankovec, and Marko Topic, Laboratory of Semiconductor Devices, Ljubljana, Slovenia;
Edited by Brad Thompson and Fran Granville] |
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Build An Audible Milliohmmeter - This project uses a four-point resistance
measurement process also known as the Kelvin method. This procedure uses a
current source to determine the value of an unidentified resistance. A constant
current flows through the unknown resistance and the voltage drop across it is
measured. Note that the current source and voltage measurement wires are soldered
together at the test prod tips Figure 2....(circuit added 03/09) |
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Build this add on Capacitance Meter - This simple add-on capacitance meter
has been specially designed to help you identify capacitors from 1p to 10u. There has
always been a problem identifying capacitors, due ….(schematic / circuit added 05/07 |
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Build your own bypass-capacitor tester |
| - 6-Dec-01 Issue of EDN Most circuits
use bypass capacitors and can deliver substandard performance if the capacitors have
poor pulse characteristics. Few if any articles cover how to test bypass capacitors
for pulse characteristics. The circuit in Figure 1 tests these characteristics. It
charges the capacitor under test through 100 kU for approximately 1 msec and then
discharges it through 10U for a.... [Design Idea by Carl Pugh, Pugh Magnetics, Newark,
CA] |
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Build your own LF/Audio instruments - Devoted entirely to Amateur radio….
[Jan-Martin Nøding's site] |
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