neon indicators

[Don Tillman]

   From: "danial stocks" <diode at hotmail.com>
   Date: Tue, 21 Nov 2000 17:47:29 

   >Hi Ken, have you ever seen one of paia's tube preamps?
   >They use a 4049 inverter powered voltage tripler that
   >gives up about +40V from a +12Vsupply. 

   Yeh you can add up more stages quite easily... 555 is also good in
   this app, can source quite a bit of current out of it.. 

I recently replaced the electronics in my Wurlitzer electric piano and
came to a similar situation; I needed a low current source of about
160 volts for the capacitance pickup.  The original piano used a high
voltage transformer, but I wasn't going to use the original
transformer for magnetic field reasons.  Instead I used a low voltage
(36 vct) torroidal transformer for my power supply, built a voltage
multiplier circuit off of the secondary, and added a simple shunting
zener regulator.

Since the center tap of the transformer is grounded, a five stage
voltage muliplier circuit actually multiplies by 4.5.  This gives me
about 220 volts and provides plenty of headroom for the zeners and
any line voltage droop.  It works very well.

Unless you're interested in battery powered operation, I don't see a
need for a high frequency oscillator.

  -- Don

-- 
Don Tillman
Palo Alto, California, USA
don at till.com
http://www.till.com