Crystal Radio Circuits - Alternative Concepts

 1. The first is the well-known, parallel-tuned, series-fed circuit. In this configuration, output to the phones is the parallel-resonance voltage, clipped by the series diode.

Parallel-tuned, series-fed Crystal Radio circuit
2. The alternative is the series-tuned, shunt-fed one. In this, output to the phones is the series-resonance current, clipped by the shunt diode.

Series-tuned, shunt fed Crystal Radio circuit
3. Another alternative is the not-so-well-known, series-tuned, shunt-fed variant.

Series-tuned, shunt-fed Crystal Radio variant