diodes

A basic description of the diode is the one way electrical valve analogy, but the diodes can be employed in other positions.would anyone care to elaborate.

 

The "one way" property is certainly the most frequently exploited feature of a diode. This is used in power supplies to rectify a.c. to d.c.

You will also find them across inductors such as relay coils where they inhibit the development of destructively high voltages when the operating curent is switched off.

If they are reverse biased they also behave like capacitors, the value of capacitance varying inversely with the applied voltage. This characteristic is used for tuning resonant circuits using specially fabricated diodes called "varicaps" or "variable capacitance diodes."

Specially manufactured diodes with a well-defined reverse-breakdown voltage, known as zener diodes, are used as (rather crude) voltage stabilisers.

And diodes are used as the most basic of mixers (detectors) in r.f. circuits.