The anode is biased to a high positive voltage (typically +1 kV to +30 kV) relative to the emitter so as to accelerate electrons from the emitter towards the anode, thus creating an electron beam that passes through the Wehnelt aperture.
The anode is charged to a high positive voltage (typically +1 kV to +30 kV) relative to the emitter so as to propel electrons from the emitter towards the anode, thereby generating an electron beam that passes through the Wehnelt aperture.