Class E Amplifiers
In a class E amplifier, the transistor is only switched on when voltage across it is zero. This condition dramatically reduces the impact of its internal capacitance on efficiency and performance at high frequencies. This elimination of switching losses is key to the high efficiency of class E amplifiers compared to other RF amplifier designs.
L1 is a large value inductor (RFC). L2, C1 and C2 are designed to resonate at the required operational frequency.
Collector voltage of a class E amplifier. The transistor is on for half a cycle and off for half a cycle.Â
When the transistor is on the collector voltage is zero and energy is stored (built up) in (RFC) L1.
When the transistor is off the built up energy is transferred to C1 and the resonant circuit.
6.9 MHz Class E amplifier
MOSFET class E amplifier.