Inverter
Disclaimer
The output of the inverter is more than 120VAC. Do not attempt construction of a device such as this unless entirely familiar with high-power electronics as well as proper safety procedures. The author specifically disclaims any and all liabilities associated with the construction and use of such devices. The design is presented here in the interests of providing information on experiments only.
This simple inverter can power up a 13W tube with a 6V SLA battery. I experimented the circuit twice, using a custom transformer and a modified power transformer respectively. The schematic diagram is shown below.
The only custom part is the transformer. I used a toroid core. The outer diameter is 1-1/8", the inner diameter and the height are 1/2". It took me 2 hours to make the windings. When I built the second unit, I modified an AC adapter, it saved me a lot of work. The power transformer rated 120/9V 1A and had only one secondary winding. I splitted the winding into two. See below for how to do it
Modification Of The Power Transformer
1. Open the case of the adapter. 2. Cut away part of the bobbin at the secondary side.
3. Pick a turn which is around the 4. Solder wires to the cut turn and remove
middle layer and cut it. the rectifiers and the capacitor.
5. Plug the adaptor to a wall outlet and check the AC voltages of the secondary windings. The best voltage ratio is 1:2. I tried the first adaptor and the voltage ratio turned out to be 1:9. That one didn't work because the voltage fed back is too low. Then I tried the second adaptor and the voltage ratio was 1:3. That one works.
6. Notes:
6.1 Caution: High voltage is present at the primary winding. It could be dangerous.
6.2 If the circuit doesn't work, swap the polarity of one of the secondary windings.
6.3 The transistor needs to be installed on a heat sink.
6.4 The circuit draws more than 1A current.
Finished units
The first unit (used a custom made toroid).
The second unit (used a modified power transformer)
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End of the project
