I hooked up a power cord and plugged the clock into the wall, but nothing happened. How come?
DON’T EVER DO THAT AGAIN! I repeat, DON’T EVER DO THAT AGAIN! The clocks you see on the wall in school, the ones without a second hand, are called impulse clocks. They DO NOT have the capability to keep time on their own. Plugging them into 110VAC household current is dangerous for you and the clock. Impulse clocks, or more commonly, slave clocks, receive a low-voltage impulse from a master clock, usually located in the main office of the school or commercial building. This low-voltage impulse activates an electro-magnet in the clock, and then releases it when the impulse ends, causing the hands to advance one minute. That’s why you usually hear two clicks, one for magnet ‘on’, the other for magnet ‘release’. Plugging an impulse clock into 110VAC household current is a sure-fire way to destroy the clock, and puts you in immediate danger of electrocution. If your Standard Electric clock DOES have a second hand, then it may run on 110VAC. Be forewarned that some of the clocks ran on 24VA
