Crystal Radio
 |
 1N34A Germanium Diodes Used in Crystal Radios New 10 Pack $5.95 Time Remaining: 16d 10h 42m Buy It Now for only: $5.95 |
 OLD CRYSTAL RADIO WITH HEADPHONES $42.00 (9 Bids) Time Remaining: 8h 22m |
 c1920 SCARCE Antique Deco Crystal Dyne Detector Radio ExceptionalWorking $300.00 Time Remaining: 15h 31m Buy It Now for only: $375.00 |
 Mystery crystal radio $39.99 Time Remaining: 15h 12m |
 1 Gang Broadcast Air Variable Capacitor 14 365PF For Crystal Radios QRP Etc $15.95 Time Remaining: 21d 10h 44m Buy It Now for only: $15.95 |
 Vintage Remco Crystal Radio with Headphones Kit Radiocraft Kit in OB $50.00 Time Remaining: 12h |
 Remco Radio Science Crystal Set with Box Instructions $2.30 (3 Bids) Time Remaining: 2d 5h 40m |
 Crystal Radio receiver The Wireless Shop Miamisburg Ohio $19.99 Time Remaining: 4d 9h 11m |
 Poly Film Variable Tuning Capacitor For Broadcast Band 265pF New $4.95 Time Remaining: 18d 4h 4m Buy It Now for only: $4.95 |
 very good working and good looking crystal radio $50.00 (1 Bid) Time Remaining: 1d 15h 39m Buy It Now for only: $175.00 |
 CRYSTALDYNE CRYSTAL RADIO AND HEADPHONES $74.99 Time Remaining: 3d 12h 57m |
 Vtg United Cabinet Crystal Unit For Radio Antenna $102.50 (3 Bids) Time Remaining: 3d 14h 18m |
 New and improved Super Tuner Duel Band Crystal Radio Kit $73.95 Time Remaining: 29d 7h 25m Buy It Now for only: $73.95 |
 REMCO RADIOCRAFT CRYSTAL RADIO SET 1960s $24.99 Time Remaining: 2d 17h 5m |
 Beautiful RARE 1920s Brush Pottery Green Bug Mystic Crystal Radio NR $327.33 (5 Bids) Time Remaining: 3d 6h 38m |
 Fahnestock Clips For Crystal Radio Projects Other Breadboarding Pack of 100 $27.95 Time Remaining: 29d 19h 12m Buy It Now for only: $27.95 |
 10 NEW SYLVANIA 1N34A VINTAGE CRYSTAL RADIO DIODES $11.08 (2 Bids) Time Remaining: 10h 44m |
 Vintage TINY TIM Pocket Toy RADIO Remco Excellent Condition includes box $36.00 (4 Bids) Time Remaining: 13h 21m |
 General Radio 1650A Impedance Bridge $45.00 Time Remaining: 3d 3h 1m |
 EARLY PHILMORE NEW YORK CRYSTAL RADIOESTATE FIND $28.00 Time Remaining: 6d 18h Buy It Now for only: $28.00 |
 Crystal or Tube Radio Capacitor Tuning Coils and Form for Amateur Building xtal $5.00 (1 Bid) Time Remaining: 1d 15h 45m |
 Superb 100 Original 1921 RCA Aeriola Jr Crystal Radio w Orig Perikon Detector $338.00 (13 Bids) Time Remaining: 15h 32m |
 Crystal Rocket Radio straight from the 1950s $0.99 (1 Bid) Time Remaining: 5d 8h 51m Buy It Now for only: $45.00 |
 Fahnestock Clips For Crystal Radio Projects Other Breadboarding Pack of 10 $4.99 Time Remaining: 7d 17h 1m Buy It Now for only: $4.99 |
 Vintage 1920 BTH Radiola Bijou Crystal Radio Form B $118.55 Time Remaining: 7h 36m |
 Mighty Atom Galena Crystal Britains Best with tweezers in metal case $9.99 Time Remaining: 3d 11h 19m |
 Pre Wound Coil Form 350uH Ideal for Crystal Radios $4.95 Time Remaining: 20d 9h 42m Buy It Now for only: $4.95 |
 RARE NICE VintageTrimm Dependable Earphones for Crystal Radio Use MUST SEE $49.95 Time Remaining: 16h 20m |
 Nathaniel Baldwin Head Set Ear Phone Type C Original Collectible Box 1910 1915 $29.99 (1 Bid) Time Remaining: 2d 12h 33m |
 Antique 1920s Westinghouse Aeriola Sr Radio Receiver RCA Crystal Tube WD 11 $32.00 (5 Bids) Time Remaining: 3d 13h 23m |
 Mini 4 Gang Poly film Variable Tuning Capacitor 320pF Great for Crystal Radios $5.95 Time Remaining: 11d 5h 3m Buy It Now for only: $5.95 |
 ALL ABOUT CRYSTAL RADIOS+33 BOOKS ARTICLES A FREE LIBRARY ON CD ROM $4.50 Time Remaining: 16h 17m |
 1920s WECCO Jr CRYSTAL DETECTOR RADIO RECEIVER WOOD CASE ORIGINAL $315.00 Time Remaining: 16h 54m |
 Crystal Detector Radio SELEKTOR II Germany Detektor Empfnger $90.00 (8 Bids) Time Remaining: 1d 16h 32m |
 New custom wound coil for the Mystery Crystal Radio $18.95 Time Remaining: 10d 8h 17m Buy It Now for only: $18.95 |
 Navy Sound Powered Headphones Elements Pair for Crystal Radio $9.00 Time Remaining: 3d 4h 27m Buy It Now for only: $9.99 |
 Vintage Murdock Crystal Radio Detector As Is $109.99 Time Remaining: 4d 4h 26m Buy It Now for only: $129.99 |
 Fahnestock Clips For Crystal Radio Projects Other Breadboarding Pack of 20 $7.90 Time Remaining: 16h 20m Buy It Now for only: $7.90 |
 Vintage Crystal Radio from 1930 $19.99 Time Remaining: 22h 51m |
 VINTAGE CRYSTAL SET KIT NO115 $29.99 Time Remaining: 1d 5h 55m |
 Crystal Radio Tuner Dial $1.00 Time Remaining: 1d 9h 40m Buy It Now for only: $22.00 |
 Crystal Radio Basket weave Coil Winding Form kit Get Higher Q $12.00 Time Remaining: 25d 10h 38m Buy It Now for only: $12.00 |
 Manhattan Molded Bakelite Variometers Variocoupler Crystal Tube Radio Homebrew $26.00 (2 Bids) Time Remaining: 4d 12h 12m |
 Vintage Rare Sonar Fr 2515 Sonar Scan Police Scanner Crystal Reciever Scanner $49.99 Time Remaining: 16h 41m |
 Realistic Crystal Controlled Weatheradio Model No 12 152A by Radio Shack $8.99 Time Remaining: 17h 9m |
 1N34A Germanium DiodeTV FM AM Radio Detection1N34x10 $7.49 Time Remaining: 4d 56m Buy It Now for only: $7.49 |
 Vintage Space Age 1 Transistor Radio $49.99 Time Remaining: 22h 49m |
 Navy Sound Powered Headphones Elements Pair for Crystal Radio $9.00 Time Remaining: 3d 4h 28m Buy It Now for only: $9.99 |
 EARLY WESTINGHOUSE TUBE CRYSTAL RADIO BOXED WITH DIAL TUNER BATTERY $43.59 (4 Bids) Time Remaining: 4d 17h 1m |
 1N60 Germanium DiodeTV FM AM Radio Detectionx 20 $5.50 Time Remaining: 6d 23h 34m Buy It Now for only: $5.50 |
 x6 vintage coils inductors ceramic core for crystal HAM radio 01 03 mH $18.00 Time Remaining: 2d 12h 16m Buy It Now for only: $24.00 |
 C Brandes Radio Head Phones Headphones Nice condition Cords Headset $9.99 Time Remaining: 3d 15h 7m |
 Crystal Earpiece $3.90 Time Remaining: 7d 4h 5m Buy It Now for only: $3.90 |
 Variable coupler Crystal Radio NO RESURVE $0.99 Time Remaining: 7d 15h 25m |
 crystal radio with Speakers $85.00 Time Remaining: 4d 11h 32m Buy It Now for only: $105.00 |
 Vintage Remco Master Electrocraft Workshop Kit 403 Signal Station Plus $50.00 (1 Bid) Time Remaining: 14h 45m |
 Crystal Radio How To Build Books Plans Library CD $12.95 Time Remaining: 2d 4h 39m Buy It Now for only: $12.95 |
 x3 Vintage QUARTZ CRYSTAL Filter XTAL Glass TUBE Envelope RARE $265.00 Time Remaining: 2d 12h 18m Buy It Now for only: $295.00 |
 GREAT and RARE CRYSTAL RADIO PLANSNEWSCONSTRUCTION1930 1960yr $3.00 Time Remaining: 16h 9m Buy It Now for only: $3.30 |
 Navy Soundpowered Headphone Elements Pair for Crystal Radio $9.00 Time Remaining: 3d 4h 23m Buy It Now for only: $9.99 |
 Diamond weave Coils for Crystal Radio Sets with 2 free 1N34A Diodes $20.00 Time Remaining: 14d 2h 57m Buy It Now for only: $20.00 |
 NEW OLD STOCK EARLY PHILMORE RADIO CRYSTAL IN ORIGINAL BOX EXCELLENT COND WOW $22.00 Time Remaining: 3d 12h 12m Buy It Now for only: $25.00 |
 Vintage Crystal Glass WNYC NewYork radio microphone paperweight box papers $20.00 Time Remaining: 4d 17h 13m Buy It Now for only: $35.00 |
 VINTAGE WORKING HEATHKIT CR 1 CRYSTAL RADIO RECEIVER $174.50 Time Remaining: 19d 7h 8m Buy It Now for only: $174.50 |
 Cats Whisker Galena Detector for Crystal Radio Wireless Set 1920s $15.95 (1 Bid) Time Remaining: 5d 6h 20m |
 LOT OF RADIO ITEMS SIGNAL CORPS CRYSTAL RESISTORS TUBES ETC $7.99 Time Remaining: 7h 21m |
 NEW OLD STOCK IN ORIGINAL BOX OLD PHILMORE RADIO FIXED CRYSTAL DETECTOR WOW $45.00 Time Remaining: 3d 11h 27m Buy It Now for only: $50.00 |
 Crystal Set Signal Strength Meter $12.99 Time Remaining: 2d 4h 16m Buy It Now for only: $12.99 |
 Diamond Crystal Salt AM Transistor Radio 1970s Food Promo Works Complete w Box $15.00 (1 Bid) Time Remaining: 14h 41m |
 VINTAGE HALLICRAFTER TUBE CRYSTAL HAM RADIO CB 7 CITIZENS RADIO TRANSCEIVER $19.99 Time Remaining: 3d 6h 10m |
 VINTAGE BRUSH CRYSTAL RADIO HEADPHONES BAKELITE AS IS BROKEN WIRES $14.99 Time Remaining: 5d 13h 57m |
 VINTAGE WORKING KENT MG50 GERMANIUM CRYSTAL RADIO IN BOX WITH EXTRAS $69.50 Time Remaining: 2d 6h 21m Buy It Now for only: $69.50 |
 Vintage ROYALFONE KING OF ALL Headphones headset electrical Newark NJ $9.99 Time Remaining: 1d 11h 6m |
 EARLY VINTAGE CIGAR BOX SHORT WAVE CRYSTAL RADIO $29.99 Time Remaining: 5d 13h 53m |
 Gillette Blue Blade Crystal Radio Detector Kit $11.00 Time Remaining: 4d 20h 30m Buy It Now for only: $11.00 |
 SUPERB BAKELITE GERMANIUM MINIATURE POCKET CRYSTAL RADIO H G JAPAN BOXED $126.44 Time Remaining: 10h 36m |
 VINTAGE 1961 SONAR VHF SENTRY POLICE FIRE MODEL FR 103 S CRYSTAL CONTROLLED $9.99 Time Remaining: 4d 2h 50m |
 VINTAGE McMARTIN TR E5 CRYSTAL CONTROLLED TALKING BOOK RADIO RECEIVER WORKING $49.99 Time Remaining: 5d 6h 52m |
 VINTAGE WORKING HEAREVER ROCKET GERMANIUM DIODE CRYSTAL RADIO $64.50 Time Remaining: 7d 7h 8m Buy It Now for only: $64.50 |
 Realistic Crystal Controlled Weatheradio Model 12 141 GREAT FOR CAMPING HIKING $0.99 Time Remaining: 3d 12h 19m |
 Antique Australian Crystal Set Radio THE ELROY Homecrafts Bakelite Melbourne $246.60 Time Remaining: 4d 21h 21m |
 well built crystal radio $76.00 (9 Bids) Time Remaining: 6d 8h 23m Buy It Now for only: $250.00 |
 Lot of 100 Germanium Diodes 1N34A Glass $26.97 Time Remaining: 9d 5h 53m Buy It Now for only: $26.97 |
 CRYSTAL RADIO SHORTWAVE ARC 5 RECEIVER 3 GANG 5 AIR TRIMMERS VARIABLE CAPACITOR $11.95 Time Remaining: 6d 5h 51m Buy It Now for only: $15.95 |
 MATCHED PAIR 2 JOHNSON MESSENGER 110 RADIOS W POWER SUPPLY MINT NOS 1968 5 CHN $69.00 Time Remaining: 2d 17h 26m Buy It Now for only: $150.00 |
Crystal radio to power an LED?
I want to make something like a crystal radio to light up a small LED. I am not near a station, so I am guessing it wont be enough to power an LED, so what if I use a capacitor to collect the energy and then only light up the LED for a few seconds at a time?
Is this possible and if it is how can I do it?
First poster:
But what if I store the energy with a capacitor or something so that the LED lights up for a second say every, 5 minutes?
I've tried to find a quick-and -easy solution for what you propose, actually I'm pretty sure it's possible even if you are limited to 40uW. You can, instead of flashing it for one second every 3-400, flash it for only about 1/20th of a second evry 15-20 seconds. Same amount of energy, and it will be visible. Rather than detect the signal with a diode, step up the voltage thru an aircoil tapped choke. Rectifiy it, apply to perhaps a 10nF cap. Then the tricky part - you need some sort of triac-type of device, that once triggered by a threshold voltage will dump the charge on the cap to your LED. Thing is, you can't use bipolar transistors like a traic uses, the leakage current is too high - the cap will never charge. Perhaps a triac made out of FET's?
I built something similar years ago, it was a very small coil connected to a circuit similar to the one just descibed. It pulsed an LED at a rate somewhat proportional to the magnetic field the coil was in. I was building chargers and charging coils for battery-powered implantable medical devices which could be recharged via a magnetic field. I need a sensor for measuring and mapping in 3D field strengths at better than 1cm resolution, but the only commercial field probes I could find were at least 10 times as large. Anyway, I built it and it worked, but these were strong fields, over 100 gauss. Bipolar triac was fine. Your app is a bit more challeging. Good luck, it's an interesting project, email me if I can help.
[[REPOST]]
Don't let others discourage you, I guarentee it can be done if you really want to make it happen. Ceramic caps have leakage in the femptoamp range and can store charge for years. The trickest part will be the FET traic biasing, such that it turns on hard once triggered rather than assume a steady state. I remember having a helluva time with that.
