Crystal Radio
A crystal radio uses no active parts: it is powered only by the radio signal itself, whose detected power feeds headphones in order to be audible at all. In order to achieve even a minimal sensitivity, a crystal radio is limited to low frequencies using a large antenna (usually a long wire). It relies on detection using some sort of semiconductor diode such as the original cat's-whisker diode discovered long before the development of modern semiconductors.
- Advantages
- Simple, easy-to-make. Here we see a classic design for a clandestine receiver in a POW camp.
- Disadvantages
- Insensitive, it needs a strong RF signal and/or a long-wire antenna to operate.
- Poor selectivity since it only has one tuned circuit.
Read more about this topic: Radio Receiver Design
Famous quotes containing the words crystal and/or radio:
“Wynken, Blynken, and Nod one night
Sailed off in a wooden shoe—
Sailed on a river of crystal light,
Into a sea of dew.”
—Eugene Field (1850–1895)
“England has the most sordid literary scene I’ve ever seen. They all meet in the same pub. This guy’s writing a foreword for this person. They all have to give radio programs, they have to do all this just in order to scrape by. They’re all scratching each other’s backs.”
—William Burroughs (b. 1914)