The ACT25 also had a CV number of CV436 is an air cooled external anode triode. The prototype was the E1996 from M-OV. It was designed for RF power generation in the UHF region between 500 MHz and 1 GHz.
This triode was designed for forced air cooling of the anode. The maximum dissipation is 450 Watts.
The ACT25 was used as a 50cm RF amplifier in the type 232 Radar. This exhibit has the copper and brass external sections as pristine as new unlike our other ACT25.
The ACT22 and ACT23 were introduced in 1947, the ACT23 being very similar in external appearance to the ACT25.
The heater connection. The serial number is 8017. The perforated brass ring is the grid connection.
The cathode is the copper ring on the left.
The central anode with folded strips making up the large surface area required to cool the anode by a forced air flow. The air is confined to the anode region by the outer brass cylinder.
A closer view of the cooling fins. Within the brass cylinder thay cab be seen to be a single folded strip with loops touching both the anode and the brass outer cylinder. However, at the open end where air is admitted the outer tops of the loops have been machined away so that air passed across both sides of the strip.
The disc seal envelope is 51 mm in diameter, and including the base pins is 130 mm tall.