Quote:
Originally Posted by vortalexfan
I said it looks like an early version of a veractor tuner, and the reason why I said that was because this TV uses push buttons to tune the stations in on the TV much like how the Veractor tuners work, except that unlike a veractor tuner the pushbutton channel settings on this TV are fixed rather than tunable to different stations like the veractor tuners are.
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A varactor is a diode that is specially designed so that the capacitance of the PN junction varies in a wide linear fashion in direct relation to the voltage applied to the junction...a varactor tuner in it's earliest/simplest form is just a single knob connected to a potentiometer that changes the bias on the varactor diode.... the push button varactors (and the modern computer controlled rapid access tuners) are just fancier control schemes.
In the early post WWII period there were a lot of conventional LC reconant circuit tuners that used push buttons. Halicrafters , Silvertone (made by colonial radio), Teletone, and probably a few others all made at least 1 model with pushbutton controlled LC tuning....back then electronic presets and the switch mechs were common in higher end radios and it often required little more than a doubling of the button count to use one of those mechs....the rotary knob tuners (ignoring the handful of variable capacitor and variable inductor based odd balls) were the exact same electrically as the push button tuners of the time only they simplified the mechanism to reduce cost and the number of moving parts.