2 transistor Crystal radio amplifier kit - shortwave science fair Answered
This kit is 5.00 dollars . To order send email. Then send check. The amplifier has the parts soldered on top of homemade circuit board. It is tested . I listen for KCBS, KGO,kSCO and several other stations with only a small ferrite on a crystal radio.. Only the circuit board is included. The coil and tuning capacitor are not included. Many coil and variable capacitor combinations will work up to about 13 Mhz. There is a small wire near the output which provides feedback when it is moved towards the input. Each station is tuned individually as the feedback is different. Wrap several turns around the input coil (not included). The variable capacitor is in parallel with the coil. The shortwave coil can be a 1 inch diameter with 13 turns of narrow wire. Stations I pick up are Radio Havana Cuba, Radio New Zealand , Church and amateur. There are some cautions. It could include cutting tape for your circuit design. The shortwave requires an external antenna. Schematic included. Crystal earphone is not included. Another transistor can be added for speaker or 8 ohm type earphone.