This board goes with my Instructable on making a Neon Lamp Tea Light.

I acquired a bag of NE-2 neon indicator lamps, which glow orange when you supply them with about 90V DC or 60V AC. I thought it would be cool to make a portable device that lights up using one of these bulbs, since they're usually found in old, clunky, high-power electronics. I used an LT1073 DC/DC converter to step up 3.7V to 80V DC, and also a MCP73831 single-cell Lipo charge controller to recharge the battery. A surface-mount LED turns on while the battery is charging, and turns off when the battery has finished charging. As explained in my Instructable, I used a Qi wireless charging receiver to charge the battery, which means the device recharges when placed on any Qi-standard wireless charging pad.

Even if you're not going to follow the Instructable, you can use this board to make a portable and rechargeable variable voltage supply. Simply make R4 a 0 ohm resistor (a short), R10 a 22k resistor, and replace R3 with a 10k potentiometer. This will give you a low-power adjustable supply that outputs between 65V and 95V at low currents (no greater than 3mA at 90V). The Instructable and the LT1073 datasheet will explain how to get a different range of output voltages.

If you don't want to recharge a battery with this board, then remove U2, LED1, R13, R11, R5, R6, R7, R8, R9, R12, C4, D4, and Q2. In this configuration, the stepup converter should function properly while the voltage at VBAT is between 1.5V and 5V, although the maximum output voltage may be limited at lower input voltages.