I am working on a simple FM radio transmitter and I was looking for a variable capacitor to help tune the circuit. I rummaged around and took apart an old Sony radio that had this component in it. Something tells me that it is a variable capacitor, but I wanted to ask this question to verify it:
The top white disk is rotate-able.
I tried the bottom terminals with a multimeter's capacitance function, but it appeared to have no capacitance. Has anyone ever seen this device?
Another quick question: I heard that transistors can act as voltage-controlled capacitors. Is this true? Is this why people use transistors to control the oscillations on their radios?