09-12-2021, 02:10 PM
I am just thinking via the forum here and would appreciate your thought's on the matter.
I am building the Horizontal frame output for the NBTV project, I have a couple of EF91's providing a god 12.5Hz sawtooth with a reasonably quick flyback. To driving the scan coils the only way that comes to mind, is as before with an EL84 driving a transformer to connect with the scan coils. The issue is the 12.5Hz frequency.
I need 5 watts max to drive the scan coils, 50 Volts swing at a peak of 100mA. So I am thinking of trying a minimum 25 VA mains transformer as it may not become saturated at 12.5Hz.
Ideally I need a 3:1 transformer with just over 50 Volts output, but trying to see if the idea works first with something a bit easier to get hold of. Would appreciate thoughts?
Adrian
I am building the Horizontal frame output for the NBTV project, I have a couple of EF91's providing a god 12.5Hz sawtooth with a reasonably quick flyback. To driving the scan coils the only way that comes to mind, is as before with an EL84 driving a transformer to connect with the scan coils. The issue is the 12.5Hz frequency.
I need 5 watts max to drive the scan coils, 50 Volts swing at a peak of 100mA. So I am thinking of trying a minimum 25 VA mains transformer as it may not become saturated at 12.5Hz.
Ideally I need a 3:1 transformer with just over 50 Volts output, but trying to see if the idea works first with something a bit easier to get hold of. Would appreciate thoughts?
Adrian
Learning as I go!
Youtube EF91 Valve
Youtube EF91 Valve
