Repeat this test, but this time use a bit of cloth to write the letter "A" on a plastic book cover in invisible, negative net-charge.
Remove the comb and the LED brightens again. Take a second plastic rod or plastic pen! Voltages above 60V are a shock hazard! Let some poor fool examine the sensor, yell at it, etc.
The electroscope can be designed for bench-mounting or more compactly inside a gluestick tube with identical metallic detector plates on the cap. This indicates that the comb has an excess of negative electric charge, and the FET responds to the electrostatic field surrounding the comb.
Try connecting the gate wire to earth ground, then suspend the rest of circuit with an insulating handle. Note that a metal comb will not work, since any separated electric charge immediately weakens by spreading to your hand and across your whole body. Some have a switch that allows the operator to select automatic tuning or manual tuning.
Hold the circuit in your hand, make sure the LED is lit, stand on a rug, then jump up and down.
The electron-sea of a metal is not very compressible. If you are considering electronic prospecting, it is best to use tools designed for the job.
Can you see the "A" when you sweep the stick back and forth? Hunting for nuggets, veins, and paystreaks in highly mineralized areas is a natural application. Any small sparks jumping from your finger to the Gate wire can damage the transistor internally.
An Electroscope is a new breed and concept of metal detector technology. Make sure that the transistor is connected similar to the little drawing above. The LED will go dark. Gold and silver coins, jewelry and precious metal artifacts have been recovered.
Fondle the whole pen with slightly damp hands if not.
Metals act as conductors NOT because charge can pass through them. Some burglar alarms do as well. Two CR 3V cells are used to power the circuit. In the middle of the red lines will be a black splotch caused by the electrostatic field surrounding the negative object!
It would be like pinching a hose shut, so no liquid could flow. Electroscope is a bird dog for treasure hunters to get them into the immediate area of the gold and silver.
I blew away my allowance for weeks to buy that tube plus a 6. I would be like turning off a switch, but almost no Electronic electroscope is required to do this. Hold each near the sensor.
Or, touch a plastic pen to some hair, then wave it near the sensor, and the LED will light up. Also, try taking two strips of tape, stick them back to front fold little tabs so you can separate them again, pat them down with moist hands to discharge them, then peel them apart. Your hand causes the e-field around the object to distort and change.
The FET detects the potential difference created by the 9V battery, just as it detects the much larger potentials in the space around electrified objects. An electronic locator to recognize the presence of metals from long distance, up to two miles away on sizeable targets.
Have everyone build FET electrometers. These electrons leak through the gate input into the other parts of the circuit. You will discover that the roll of tape has an opposite polarity compared to the strip of tape. Polarity of operation has been reversed. So, a metal object is like a tank of "fluid electricity," and a metal wire is like a full pipe.
Demonstrate to onlookers that the sensor does not respond when you shake it up and down, but it does respond when you jump.
Hold it high in the air, then lower it to the ground while watching the LED. You are actually sending out radio waves with nearly zero frequency when you do this. When the gate lead is electrified negative, it repels the electron-gas out of the silicon and converts it into an insulator.
The value of any detector technology is determined by what the operators find with it.PDF | An electronic electroscope has been constructed to update the design of a similar instrument reported in Physics Education several decades ago.
The presence of positive or negative charges. An electroscope is the instrument used to detect charged bodies. Here is an electronic version of the scope that is sensitive and, unlike conventional scopes, indicates the polarity of charge as well.
This circuit consumes very low quiescent power and reliably indicates charge induction and. An electronic electroscope has been constructed to update the design of a similar instrument reported in Physics Education several decades ago.
The presence of positive or negative charges is easily distinguished with this electroscope and an experiment with a Faraday cup is carried out to show how. Editor's Note: The last electroscope I used employed gold leaves or pith balls to indicate charge, but here's an electronic version with no moving parts.
Though one of our reviewers felt the design was not robust or repeatable, I thought it was interesting and unusual enough to warrant inspection by our readers.
Electronic and Electrical Servicing, Second Edition: Consumer and Commercial Electronics [Ian Sinclair, John Dunton] on ultimedescente.com *FREE* shipping on qualifying offers.
Electronic and Electrical Servicing provides a thorough grounding in the electronics and electrical principles required by service engineers servicing home. An Electroscope is a new breed and concept of metal detector technology.
An electronic locator to recognize the presence of metals from long distance, up to two miles away on sizeable targets. The operator adds discrimination by advancing the discrimination knob to eliminate unwanted metals while gold and silver remain good targets.Download