🔍 Key Concepts

• Grid-leak bias in a vacuum tube and how it is produced • Role of grid-leak resistor value in setting bias voltage • How grid current flows during part of the RF cycle and why its duration matters

💭 Think About

• Think about what actually creates the negative bias on the control grid in a grid-leak circuit: is it current, resistance, time, or some combination? • Ask yourself: to develop a voltage across any resistor, what basic electrical relationship applies, and which terms in that relationship can you control in a grid-leak circuit? • Consider whether the tube’s internal resistance between grid and cathode is usually a design variable you choose, or a tube characteristic that stays mostly fixed.

✅ Before You Answer

• Review how Ohm’s Law (V = I × R) applies to the voltage developed across the grid-leak resistor. • Confirm what causes grid current to flow only on certain parts of the RF cycle, and how that affects average grid bias. • Decide whether internal grid‑to‑cathode resistance is normally treated as a primary adjustable design factor in grid‑leak bias circuits.