Question about dual gang air variable capacitor connections

[obrien135]

Hello,

My next question is:

Why are there two solder terminals on the stators (on opposite sides) of a lot of dual gang caps. Do you have to connect both?

George

 

[RCinFLA]

Typically, one is used for RF tank tuning, other for local oscillator tuning. For an AM radio they are typically slightly different sizes to get better tracking. You can also achieve tracking by adjusting a fixed series capacitor to achieve proper tuning ratio for frequency tracking.

 

[krp]

I think it was just to allow flexibility in the wiring layout; in pre-PCB days the wiring was "point-to-point" and a choice of connection point would have been useful since variable capacitors could be mounted in different ways.

Both connection points could be used for different components if the chassis layout made that convenient.

You don't have to connect both.

 

[obrien135]

Thanks fellows.