The Varian CPI 845 is a high-vacuum power triode engineered for industrial heating applications. Built with rugged construction, this tube delivers high power output and excellent efficiency for demanding amplification tasks. Descended from Varian Associates’ electron tube legacy—established in 1948 and transitioned to Communications and Power Industries (CPI) in August 1995—the CPI 845 represents decades of expertise in signal generation and amplification.
Technical Specifications
Filament: 10 V AC at 3.25 A
Plate Dissipation: 75 W maximum rating; 71 W, 65 W typical operation depending on circuit configuration
DC Plate Voltage: 1250 V maximum rating; 750 V, 1000 V, and 1250 V typical operating points
DC Grid Voltage: -98 V to -209 V depending on operating class and load impedance
Peak AF Grid Voltage: 93 V to 204 V across standard Class AF configurations
DC Plate Current: 52 mA to 95 mA typical operation
Load Resistance: 3400 Ω, 9000 Ω, and 16000 Ω configurations
Power Output: 15 W typical in Class AF power amplifier and modulator modes
– Key Features
• High-vacuum triode design optimized for thermal and RF applications
• Configurable load impedance supporting 3400 Ω to 16000 Ω networks
• Multiple DC plate voltage operating points (750 V to 1250 V) for flexible system design
• Moderate filament power requirement (32.5 W nominal)
• Stable grid bias range supporting linear modulation and amplification
– Typical Applications
• Industrial heating systems
• AF power amplification
• Modulator circuits in audio and RF equipment
– Compatibility & Integration
The CPI 845 integrates into systems requiring Class AF power amplifier and modulator configurations. Circuit designers should reference load resistance and bias voltage specifications when selecting matching networks and power supply ratings.
