6CM5

6CM5 is also designated EL36.

The 6CM5 is an output pentode intended for use as a line output tube in television receivers. It has an indirect heater rated at 6.3 volts and 1.25 amperes for parallel supply, an octal base, and a top-cap connection to the plate.

## Construction

The 6CM5 is a Philips EL 36. The Philips datasheet gives dimensions in millimeters, with a maximum length of 50 mm and a maximum diameter of 33 mm.

## Ratings

Maximum ratings include a plate dissipation of 10 watts, a grid No. 2 dissipation of 5 watts, and a combined plate and grid No. 2 dissipation of 13 watts. The maximum plate voltage is 250 volts, or 300 volts for AF class B operation, with a maximum peak plate voltage of 7000 volts and a maximum peak inverse plate voltage of 1500 volts. The maximum grid No. 2 voltage is 250 volts, or 550 volts when no current is drawn. The maximum peak negative grid No. 1 voltage is 1000 volts, the maximum cathode current is 200 mA, the maximum grid No. 1 circuit resistance is 0.5 megohm, and the maximum voltage between cathode and heater is 100 volts.

## Characteristics

Typical characteristics, measured at a plate voltage of 100 volts, a grid No. 2 voltage of 100 volts, and a grid No. 1 voltage of -7.7 volts, include a plate current of 100 mA. Under these conditions the plate resistance is 5300 ohms, the transconductance is 14 mA/V, and the grid No. 2 to grid No. 1 amplification factor is 6. Capacitances include a plate-to-grid No. 1 value of less than 1.1 pF, a grid No. 1-to-all-other-elements value of 17.5 pF, and a plate-to-all-other-elements value of 7.7 pF.

## Applications

Operating conditions as a class B amplifier include a plate voltage of 300 volts, a grid No. 2 voltage of 150 volts, a plate-to-plate load resistance of 3500 ohms, an input AF voltage of 20 volts rms, and a zero-signal plate current of 2 × 18 mA. Under these conditions the maximum signal power output is 44.5 watts, with a total harmonic distortion of 7.2 percent. The Philips datasheet states that the minimum drive at Vap = 5 kV is 100 V and at Vap = 7 kV is 120 V. It also states that when the tube is operated below the knee of its Ia-Va characteristic, the screen grid series resistor must have a minimum value of 2.2 kΩ to avoid Barkhausen oscillations. The line output circuit should be designed around a current 25% lower than the values shown on pages 6 and 7 and 20% lower than the values shown on pages 8 and 9.

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.

Original manufacturer datasheets for 6CM5, hosted by Frank Philipse's Electron Tube Data sheets.

Documents held here and used to write this page.

• 6CM5
• PHILIPS EL 36 (filed under EL36)