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Eight Way Switcher - (Schematic / Circuit added 11/06)
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Electric motor - Back in the old days, before home computers,
there were certain things that technically minded boys just had to have
done, and one of those was to build a working electric motor from
scratch....[Designed by Markus Wandel] |
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Electronic Motor Starter - .... |
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Encoder and PC make complete motor-control system - 12-Dec-02
Issue of EDN This Design Idea combines a simple ISA-bus-resident interface
circuit; a garden-variety PC; a high-resolution optical shaft encoder; and a
PWM-controlled, 0.05-hp, brushed, permanent-magnet dc motor....[Design Idea
by Steve Woodward, University of North Carolina, Chapel Hill, NC] |
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Engine Control Unit Schematics - (circuit / schematic design added
6/06) |
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Fan control - As we begin to enjoy those lazy hazy days of summer,
the most important thing on most of our minds is how to keep cool during
those hot days. For some of us that means turning up the old air conditioner
and sipping on a nice cold glass of our favorite soft drink. However, we
often forget about an equally important....[Radio Amateur Society of
Norwich] |
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Fan Controller Adapts to System Temperature - 09/25/97 EDN-Design
Ideas....Any piece of electronic equipment--whether it be a lab instrument, an audio
amplifier, or a PC--that relies on a cooling fan to control internal temperature is a
potential source of noise pollution or even hearing damage. Most of the time, the
fan's noise level is probably much higher than necessary, because it has enough
capacity to move....[Design Idea by Kerry Lacanette, National Semiconductor, Tucson,
AZ] |
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Fan Dual-Controller - Each fan turns off when the temperature drops 5
degrees below its turn-on temperature. For example, if the dial is set to 80 degrees,
the fan turns on at 80 degrees and turns off at 75 degrees. This prevents the
fan from cycling on and off rapidly, which would occur if the fan turned on at 80,
started to cool the cabinet, and then immediately turned off at 79. ….(design added
11/08) |
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[_OLD-ads-dont_upload/OLD I-ADS from web/ad-djandassoc.htm] |
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Fan Speed Controller - Simple circuit for fan speed control based on thermal
feedback. To reduce product noise. Design idea was rejected! Years later companies are
making millions from such circuits.… [Jim Haggerman, Hagerman Technology LLC] |
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Fan timer based on Motorola 68HC908QT2 - (electronic circuit added 4/05)
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Flashing LED-based Solar Engine - Voltage-Controlled Solar Engine:This
design uses a flashing LED to determine the solar engine's voltage trip level.
(added 11/05) |
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Fly-back Converter - (application / block diagram added 6/07) |
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Four Way Switcher - (Schematic added 11/06) |
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Four Way Switcher #2 - (Electronic Schematic added 11/06) |
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Four-Speed Fan Control using Simple Remote Diode Temperature Sensor -
National Semiconductor Application Note (app note added 2/06) |
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Four-transistor H-bridge - an interesting 4-transistor H-bridge variant;
this is cheap and easy to build, and best of all is "smokeless" (i.e., no combination
of inputs can cause the bridge to self-destruct). (added 11/05) |
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Frequency switch - (diagram added 2/07) |
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Fridge Saver - This circuit waits 5 minutes before re-applying the power to
a refrigerator to prevent it from having to start up under pressure after a brief
power outage. This is highly stressful for the compressor and the thermal
cut-out switch built into the compressor. This device prevents frequent brief
power interruptions [Designed by Andrew R. Morris (added 10/06)] |
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Frost Alarm (Andy Collinson) - The thermistor used has a resistance of 15k
at 25 degrees and 45k at 0 degrees celsius. A suitable bead type thermistor is found
in the Maplin catalogue. The 100k pot allows this circuit to trigger over a wide range
of temperatures. A slight amount of hysteresis is provided by inclusion of the 270k
resistor. This prevents relay chatter when temperature is near the switching
threshold of this circuit. (added 2/06) |
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Full Bridge Converter - (application / block diagram added 6/07)
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Full-featured Dual H-bridge - I had always assumed that dynamic braking
would be most effective at higher speeds. However, actual tests using a Faulhaber
(micro mo) gearmotor showed that the brake would hold a motor almost stationary. These
gearmotors are so well made that I can turn the 4 mm diameter shaft with light finger
pressure. For the tests I had mounted a 90 mm diameter wheel, which gave me tremendous
mechanical advantage. I found with the wheel mounted that I could barely turn the
motor against the brake. (added 11/05) |
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Gate Boost Solar Engine - Voltage-Controlled Solar Engine: The "Gate Boost
Solar Engine" is a new (6/2002) Wilf Rigter 1381-based design. This uses an
internal voltage doubler to turn on a FET more efficiently. (added 11/05)
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