Dear Lowfers,
I am just looking to the zwischenbasis amplifier LA8Ak (late OM Jan Noding)
has published in the internet. See my edited copy of his article. I am no t
shure, whether Jan marked the polarity of the transformer correctly. Original
article: Search with google for: Zwischenbasis Amplifier LA8AK.
If the input windig is HIGH, the gate winding must be HIGH too. This is
correctly in the schematic. To prevent self oscillation, the source winding
must give negative feedback, i. e. a HIGH-signal at the gate must give a HIGH
signal at the source of the transistor. All signal are referred to ground .
The transformer circuit I have not completely checked, winding direction
must be magnetically always the same, otherwise will change polarity. It seems
to be that gate winding polarity is reversed to input polarity. Source winding
has the same polarity as gate winding. So using winding schematic, the
circuit will operate well with a 2*180° = 360° phase shift.
Do You agree with my description?
NB: I need a preamp for 136 kHz Bandfilter to prevent overload of a EKD300 rx.
Looking foreward to Your answer,
55,
Hans-Albrecht
DK 8 ND
cba
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Zwischenbasisverrstaerker.doc
Description: MS-Word document
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