A complete radio AM receiver which requires no battery power at all can be created with a few components. The classic circuit of the well-known crystal radio or crystal receiver can be based on a germanium diode as detector, or if you prefer, the original galena crystal.
Circuit shows the classic circuit. L1 is a proprietary antenna tuning coil wound on a paper tube and Cl is a matching variable capacitor (365 to 500pF).A variable capacitor can be found in old non-working transistor radios.
You can also find the diode in these sets and use it for this project. Virtually any diode can be used, and the only other circuit component is capacitor C1, connected across the output. The earphones must be a high impedance type (headphones).
An external aerial and good physical ground connection is essential for good reception.
The circuit will tune AM band radio stations not far from your home. Component layout is shown in circuit. L1 is formed by 100 turns of No. 22to 28 AWG enameled wire on a f -inch diameter paper tube
Parts List - Crystal Radio
D1 - 1N34 or any germanium diode
L1 - Coil - see text
CV - 365 to 500 pF variable capacitor
C1 - 470 pF ceramic capacitor
PHONE - High mpedance (2,000 to 10,000 ohms) phone
No comments:
Post a Comment