Definition

1. Noun:
   • A type of electronic vacuum tube: A "tetrode" is a specific kind of thermionic valve (or tube) that contains four active electrodes inside an evacuated glass envelope. These four electrodes are typically the cathode, control grid, screen grid, and anode (plate). It was developed as an improvement over the triode (three-electrode tube) to reduce unwanted capacitance and allow for higher gain and frequency operation.

Usage Examples

• Noun:
  • The early radio amplifier used a tetrode for better signal clarity.
  • Engineers replaced the triode with a tetrode to minimize the Miller effect in the circuit.

Advanced Usage

• "Beam tetrode": A specialized type of tetrode designed to suppress secondary emission from the anode, often used in audio power amplification stages.
  • The beam tetrode, like the 6L6, became famous in guitar amplifiers.

Variants and Related Words

• Pentode (n): A five-electrode vacuum tube, which is a direct evolution from the tetrode, adding a third grid (suppressor grid).
  • The pentode offered even better performance than the tetrode.

Synonyms

• Four-electrode tube: A descriptive synonym.
• Screen-grid tube: Another name highlighting one of its key electrodes.

Related Terms

• Triode (n): A three-electrode vacuum tube, the predecessor to the tetrode.
• Anode/Plate (n): One of the four electrodes in a tetrode, which collects electrons.
• Grid (n): Refers to the control grid and screen grid electrodes within a tetrode.

Noun

1. a thermionic tube having four electrodes