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Hobby Circuits designed by Dave Johnson

Last Updated on: Tuesday, October 24, 2017 03:04 PM

Text & Graphics Copyright David A. Johnson, PE  --  ALL Rights Reserved.
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Gadget Circuits
Circuits Designed by David Johnson, P.E. :

Earthquake Alarm Circuit

Electrical Device Harvests Earthworms

Harvest Earthworms with this Electrical Device

Homemade Corner Cube Reflector

Honeybee Counter

Indicate DC Current Flow

Indicates Automotive Electrical Voltage

Knocking rings Doorbell

Modified LED Night Light

Modified Shake to Charge Flashlight

Night Light from White LED

NMH/NiCd 6v Battery Tester

Ocean Wave Power Generator Demo Unit

One-Watt White LED Night Light

Optical Filter using Color Film Negative

Remote Doorbell Beeper

Scare Off Pigeons

Shadow Activated Motion Detector

Simple Circuit for White LED Night Light

Slotted Opto-Sensor used in Honeybee Counter

Sound Generator-Clicking

Tester 4-20ma Current Loop

Touch Alarm for Door Knob

Touch Switch controls a 120 VAC load

Use Color Film Negative to Make an Optical Filter

Vertical Lifting Security Gate Power Source

Voltage to Frequency Converter + 1us LED Pulse Driver

Wave Power Generator Demo System

120 VAC Touch Switch

14v LED AuxiliaryLamp with a 60 Watt Lamp

1Khz to Over 70Mhz Light Receiver

1us LED Pulse Driver + Voltage to Frequency Converter

1W White LED Night Light

4-20ma Current Loop Tester

60 Watt Lamp with Auxiliary 14v LED Lamp

6v NMH/NiCd Battery Tester

AC Current Controls Hour Meter

Automotive Electrical Voltage Indicator

Cheap Close-Up Camera Lens

Chicken Coop Door Opener with Timer

Click Sound Generator

Coin Operated Telescope

Color Film Makes Optical Filter

Corona Monitor

CT Hour Meter

DC Current Indicator 6

Demo of a Wave Power Generator System

Door Knob Alarm

Door Knock Beeper

Doorbell heard in Basement

DVD Recorder + TV Camera Make Cheap Data Logger


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  David A. Johnson, P.E. about these circuits



Imagineering Ezine    Discover Solar Energy Dave Johnson & Associates Faraday Touch Switches

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