4CM4

4CM4 is also designated PC86.

Description

The 4CM4 is a coated unipotential cathode tube, as described in the Telefunken datasheet. It has a T 6 1/2 bulb with outline drawing 6-2, a maximum diameter of 7/8 inch, a maximum overall length of 2-5/16 inches, and a maximum seated height of 1-15/16 inches. It uses an E 9-1 small button noval 9-pin base with T 1/2 basing. The mounting position is any.

Electrode Arrangement and Basing

Pin 1 is the plate, pin 2 is the grid, pin 3 is the cathode, pin 4 is the heater, pin 5 is the heater, pin 6 is the grid, pin 7 is the cathode, pin 8 is the grid, and pin 9 is the plate.

Ratings

The maximum plate voltage is 220 volts, maximum plate dissipation is 2.2 watts, maximum cathode current is 20 mA, maximum grid circuit resistance is 1.0 megohm, and maximum negative grid voltage is 50 volts. The maximum resistance between cathode and heater is 20,000 ohms. The maximum heater-cathode voltage is 100 volts with heater negative with respect to cathode and 100 volts with heater positive with respect to cathode. The maximum frequency for UHF amplification is 800 Mc. The heater voltage is 3.8 volts and heater current is 300 mA ac or dc.

Characteristics

At a plate voltage of 175 volts and grid voltage of -1.5 volts, the plate current is 12 mA, transconductance is 14,000 μmhos, and amplification factor is 68. The equivalent noise resistance is 230 ohms. The phase of transconductance is -7 degrees, and additional noise conductance is 0.5 mmhos.

Capacitances

Without a shield, the grid-to-plate capacitance is 2.0 μμf, plate-to-grid-and-heater capacitance is 2.1 μμf, plate-to-cathode capacitance is 0.2 μμf, grid-to-cathode capacitance is 3.6 μμf, cathode-to-grid-and-heater capacitance is 6.6 μμf, grid-to-heater capacitance is less than 0.3 μμf, grid-to-cathode-and-heater capacitance is 3.9 μμf, and plate-to-cathode-and-heater capacitance is 0.3 μμf. With a specified external shield of 15/16 inch diameter and 2 inch length, grid-to-plate capacitance is 3.1 μμf, grid-to-cathode-and-heater capacitance is 4.2 μμf, and plate-to-cathode-and-heater capacitance is 0.25 μμf. Space-charge capacitance (grounded cathode) is 2.0 μμf.

Source

The datasheet information is from JEDEC release #2405, March 9, 1959. The Telefunken datasheet originates from Telefunken G.m.b.H., Röhrenwerk Ulm, Ulm (Donau), Germany.

Equivalence is asserted only where the archive's own literature states it directly, in at least 40 separate documents. Tubes that merely substitute in some circuits are not listed here.

Base B9A, viewed from below (the wiring side), pins numbered clockwise from the key. Read from the datasheet's basing table and checked against it automatically — confirm against the original datasheet before wiring.

Original manufacturer datasheets for 4CM4, hosted by Frank Philipse's Electron Tube Data sheets.

Documents held here and used to write this page.

• VKV STRMÁ TRIODA (filed under PC86)
• TELEFUNKEN

1 further designation appears alongside 4CM4 in the literature but below the evidence threshold used here, so it is not listed as equivalent.