I picked up some buildings at a swap meet which have lighting installed. I believe they are grain of wheat what voltage do they work with
Various. But likely 12 volts. You could hook them up to an old DC power pack, and gradually turn up the voltage, and see what it is when they light, using a voltmeter.
Most buildings with grain of wheat bulbs factory installed use 16 Volt rated bulbs so they will work from the Accessory terminals of a power pack.
Using 12 Volts or less will make them more realistic and they will last much longer, too.
Unfortunately, grain-of-wheat bulbs come in many voltages. If these were user-installed, the builder could have used anything.
But, it's simple to test them. Take an ordinary 1.5 volt flashlight battery. If the lights look fine, your answer is 1.5 volts. If not, try combinations of batteries (in series) until you get up to 9 volts or so. At that point, you've probably got 12 volt or 16 volt bulbs. You don't want to start testing at the high end, because putting 12 volts on a 1.5 volt bulb will burn it out very quickly.
I personally use 16-volt bulbs and run them at 12 volts. The lower voltage gives a warmer glow, and greatly increases bulb life while reducing heat.
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