Any PN junction diode can be used as a variable capacitor in reverse biased mode, as well as in the forward biased mode before the knee voltage. The capacitance is usually very small as the junction ...

Modern radios are often digital affairs, in which the frequency is derived from a stable crystal oscillator and varied through a microprocessor controlled frequency synthesiser. It won’t drift, and it ...

How do you implement a variable capacitor these days? Mechanical caps are out. That leaves varactors, which work fine but require higher voltages that often are not available, and their response is ...

Of all the low-frequency oscillator configurations, the Wien Bridge has to be the friendliest and easiest to get along with. Like a faithful dog, it behaves itself regardless of the weather, is not ...

A few months ago we brought you some experiments from [Bill Meara, N2CQR], in which he investigated the use of a glue stick as the former for a permeability tuned inductor. His set-up was very much in ...

After delving into Texas Instrument’s crystal-replacing bulk acoustic wave (BAW) oscillator recently, Electronics Weekly is taking a look at an advanced version of the humble RC oscillator, reported ...