B
bhauth
- Jan 1, 1970
- 0
I'd like to build some plasma arc speakers. After all, what could
better than combining audio and high voltage?
Most designs I've seen involve using corona to produce sound. It seems
to me that this has the disadvantages of either needing a RF ground or
interfering with other electronic devices and of wasting a lot of
energy in ultrasonic current variation. And I want to do things
differently in any case.
What I was thinking I would do:
Make a especially well smoothed rectifier circuit, which goes through a
H-bridge of power BJTs,
something like
http://www.newark.com/NewarkWebComm...l.jsp?SKU=01H0845&CMP=AFC-CC3763909474&QText=
maybe. The audio input is switched between the bases of the power
transistors through small transistors. This H-bridge feeds either a
tightly coupled half-wave double-resonant solid state tesla coil or an
autotransformer cascade. The autotransformer cascade would be made
something like a tesla coil secondary, with the wire reversing
direction at each stage and with high voltage wires going up and down
the thing, and with a capacitor on the inputs to give soft switching.
The small transistors switching the base current of the larger
transistors would be controlled by a filament. The high voltage high
frequency output of the secondaries would then be rectified by strings
of diodes, something like
http://www.newark.com/NewarkWebCommerce/newark/en_US/endecaSearch/partDetail.jsp?SKU=33C1012&N=0
maybe. This rectified current then goes through a small inductor (to
filter out the resonant frequency component) and the arc that's doing
the transducing.
IGBTs are usually used for this sort of thing, of course, but for an
audio application I figured I'd want the good transconductance of the
BJTs.
It would probably be something like 60kv across it, ie +/- 30kv. More
than that and I'd get pretty sick of soldering diodes.
Any obvious flaws I'm missing here? What's worrying me now is
nonlinearity from the bridge output to the current across the arc.
better than combining audio and high voltage?
Most designs I've seen involve using corona to produce sound. It seems
to me that this has the disadvantages of either needing a RF ground or
interfering with other electronic devices and of wasting a lot of
energy in ultrasonic current variation. And I want to do things
differently in any case.
What I was thinking I would do:
Make a especially well smoothed rectifier circuit, which goes through a
H-bridge of power BJTs,
something like
http://www.newark.com/NewarkWebComm...l.jsp?SKU=01H0845&CMP=AFC-CC3763909474&QText=
maybe. The audio input is switched between the bases of the power
transistors through small transistors. This H-bridge feeds either a
tightly coupled half-wave double-resonant solid state tesla coil or an
autotransformer cascade. The autotransformer cascade would be made
something like a tesla coil secondary, with the wire reversing
direction at each stage and with high voltage wires going up and down
the thing, and with a capacitor on the inputs to give soft switching.
The small transistors switching the base current of the larger
transistors would be controlled by a filament. The high voltage high
frequency output of the secondaries would then be rectified by strings
of diodes, something like
http://www.newark.com/NewarkWebCommerce/newark/en_US/endecaSearch/partDetail.jsp?SKU=33C1012&N=0
maybe. This rectified current then goes through a small inductor (to
filter out the resonant frequency component) and the arc that's doing
the transducing.
IGBTs are usually used for this sort of thing, of course, but for an
audio application I figured I'd want the good transconductance of the
BJTs.
It would probably be something like 60kv across it, ie +/- 30kv. More
than that and I'd get pretty sick of soldering diodes.
Any obvious flaws I'm missing here? What's worrying me now is
nonlinearity from the bridge output to the current across the arc.
