[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Variable Capacitance and Inductance

Original poster: "davep by way of Terry Fritz <twftesla-at-qwest-dot-net>" <davep-at-quik-dot-com>


Tesla list wrote:

> Original poster: "David Thomson by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <dave-at-volantis-dot-org>

> Hi Gary,

> Radios are tuned to crystals precisely because inductor/capacitor only
> circuits do drift.

	SOME radios are tuned by crystals.  Many are not.
	cf any book of radio design, rf design, radio history.

	With one _not_ tuned by crystals I routinely leave it
	on, volume down, turn it up, and there is the BBC on
	SW, 'just where i left it'.  With another such, even
	older, i was listening to 'Radio Australia' (Properly: ABC
	Australian Broadcasting Company  But that confuses people
	in the US, with the OTHER ABC) one day.  Next day i snapped
	it on and there they were.  (Both to a site in Eastern MA,

	Capacitors can and do change value, as many people have
	advised.  Formulae for all (?) these effects are known
	and routinely used.  Similarly for inductors.