Hello
I am experimenting with LA-3A variations. I built the Electroluminescent Panel driver with TDA2050 and substituted the autotransformer B11184 with a cheap and conventional 24:230 V transformer (1:10 relation more or less).
In principle works fine, but experimenting the frequency response it results that shows resonance problems between the secondary transformer inductance and the (high of course) Panel capacitance.
I substituted the transformer with others and the frequency response is different, but every time bad. In really, when you are in the resonance frequency, the panel bright with intensity, and at different frequencies, the bright is attenuate
I have substituted the autotransformer with real audio transformer 1:5 (big output line transformer) with the same problems.
I have tried to put the realimentation R37 (220K) and C13 (10n) but the effect is negligible, wit other resistors is not better.
In really, if you look the waveform with the oscilloscope (channel 1 = input, channel 2 = Panel signal) looks the phase change typical in the resonance… a physics lesson.
Has any body any experience?
Thanks
Miquel
I am experimenting with LA-3A variations. I built the Electroluminescent Panel driver with TDA2050 and substituted the autotransformer B11184 with a cheap and conventional 24:230 V transformer (1:10 relation more or less).
In principle works fine, but experimenting the frequency response it results that shows resonance problems between the secondary transformer inductance and the (high of course) Panel capacitance.
I substituted the transformer with others and the frequency response is different, but every time bad. In really, when you are in the resonance frequency, the panel bright with intensity, and at different frequencies, the bright is attenuate
I have substituted the autotransformer with real audio transformer 1:5 (big output line transformer) with the same problems.
I have tried to put the realimentation R37 (220K) and C13 (10n) but the effect is negligible, wit other resistors is not better.
In really, if you look the waveform with the oscilloscope (channel 1 = input, channel 2 = Panel signal) looks the phase change typical in the resonance… a physics lesson.
Has any body any experience?
Thanks
Miquel