[SOLVED] Pulse LF signal antenna switching circuit for clip ring down

[FvM]

Has the rising enevlope in post #19 been achieved with your actual circuit? Then the resonant Q is considerable lower than indicated by the 12 Vpp to 1600Vrms voltage ratio. Something doesn't match.

 

[Robert T]

Hi FvM, The envelop in #19 is the signal from the actual circuit. Maybe the Q calculator I used was not the correct one.
The Q of the antenna is 3.

I have taken your advice and looking to increase the power to the antenna as a starter.
Hope to have the new amplifier board completed by the end of this coming week.

Cheers, Robert

 

[FvM]

I read a Q of roughly 50 from your waveform which sounds more realistic than Q of 500 in my simulations. Q of 50 gives an acceptable rising envelope, but in no way the voltage boost reported in your posts with a simple LC circuit. Something must be different.

 

[Robert T]

Hi FvM,

The voltages are straight from the oscilloscope software and the circuit is as per the posted diagram.
I noticed in your simulation that you have one end of the antenna grounded. The return from the antenna in my diagram goes back to the amplifier chip rather than ground because it is a bridge amplifier. Not sure if this will make a difference.

I tried placing a resistor between the antenna and the return to the amplifier. This resulted in lowering the voltage.
According to the documentation on the amplifier, 8 ohms is the required resistance for the output of the amplifier. Reducing the resistance increases the power from the amplifier.

I am in the process of changing the amplifier to increase the power to the antenna.
Will post the final circuit and information when it is complete.

Thanks,
Robert