PC86 — Small Signal Triode, Noval | Tubeofile

PC86

Small Signal Triode — Noval

Philips

Known Equivalents & Substitutes

4CM4

Similar Tubes (Not Drop-In Compatible)

6CM4

American designation of EC86 — 6.3 V parallel heater, not series-string compatible

Identical electricals but 6.3 V parallel heater — not a drop-in in series-string heater circuits

Electrical Specifications

Absolute Maximum

Anode Voltage (max)Max Anode Voltage220V

Anode Dissipation (max)Max Anode Dissipation2.2W

Cathode Current (max)Max Cathode Current20mA

Heater-to-Cathode Voltage (max)Max Heater-Cathode Voltage100V

Max Grid ResistorMax Grid Resistor1MΩ

Typical Operating

Anode Voltage (typical)Anode Voltage175V

Grid 1 Bias VoltageGrid Voltage-1.5V

Anode CurrentAnode Current12mA

Anode ResistanceAnode Resistance4,857Ω

TransconductanceTransconductance

Capacitances

Grid-to-Plate CapacitanceGrid-to-Plate Capacitance2pF

Grid-to-Cathode CapacitanceGrid-to-Cathode Capacitance3.6pF

Anode-to-Cathode CapacitanceAnode-to-Cathode Capacitance0.2pF

other

Max Negative Grid VoltageMax Negative Grid Voltage-50V

Equivalent Noise ResistanceEquivalent Noise Resistance230Ω

Max Anode Voltage (no current)Max Anode Voltage (no current)550V

Heater

Heater VoltageHeater Voltage3.8V

Heater CurrentHeater Current0.3A

Notes

Series-heater (300 mA) version of the EC86. Electrically identical sections — only the heater voltage/current differs (3.8 V at 300 mA vs 6.3 V at 200 mA).
Designed for grounded-grid operation at UHF. Pins 2, 6, and 8 are all connected to the control grid, and pins 3 and 7 are both cathode — this multi-pin arrangement reduces lead inductance for VHF/UHF performance.
The 4CM4 is the American RETMA designation for the PC86.
Max heater-to-cathode voltage is asymmetric: 100 V (cathode positive) vs 50 V (cathode negative). Max Rkf = 20 kOhm.
Equivalent noise resistance (Req) is 230 Ohm — unusually low, reflecting the tube's design for low-noise UHF front-end service.

Pin Layout — Noval

1Anode

2Control Grid

3Cathode

Socket-Compatible Tubes ⚠ Not electrically compatible

References