10-06-2013, 05:44 PM
OK 12V 3A smps. Tx Off load 2.1A, applied load close coupled half wave into 50 Ohms
23V. Tx 3.5A. Running without the load the Tx coil gets hot measured at 83C with the load its hotter still, but I didn't measure it. I tried running the cct through the 72 turn coil connected in series with the PSU, It was barely warm. Reducing the supply to 9V
and reducing the gate resistors to 220 Ohms (8k2 before) reduced the current to 1.4A and with the load showing 15V into 50 Ohms the current rose to 2A.
The heating effect is not due to the straight forward I and i wouldn't think skin effect either (40K) but is the major problem here, any suggestions more than welcome.
Mike
23V. Tx 3.5A. Running without the load the Tx coil gets hot measured at 83C with the load its hotter still, but I didn't measure it. I tried running the cct through the 72 turn coil connected in series with the PSU, It was barely warm. Reducing the supply to 9V
and reducing the gate resistors to 220 Ohms (8k2 before) reduced the current to 1.4A and with the load showing 15V into 50 Ohms the current rose to 2A.
The heating effect is not due to the straight forward I and i wouldn't think skin effect either (40K) but is the major problem here, any suggestions more than welcome.
Mike
