🔍 Key Concepts

• Conduction angle in amplifier classes (how many degrees of the input cycle the active device conducts current) • How Class A operation compares to Class B and Class C in terms of conduction angle • What happens to grid/base current and bias point in a typical Class A stage

💭 Think About

• For a Class A amplifier, think about whether the active device (tube, transistor) is conducting for less than, exactly, more than, or the full 360 degrees of the input signal cycle. • Ask yourself what makes Class A different from Class B and Class C in terms of biasing and when current stops flowing. • Consider whether it is accurate to say there is no grid/base current in a usual Class A circuit, or whether that depends on the specific implementation.

✅ Before You Answer

• Verify the definition of Class A operation, especially the conduction angle (in degrees) for which the device conducts. • Check whether a typical Class A tube amplifier is biased so that current flows for the entire input cycle or only a little more than 180 degrees. • Confirm if the statement "there is no grid current" is always true for all Class A amplifiers, or only under idealized small‑signal conditions.