# Please help! 120 V appliances on 100 V... **URL:** \ **Category:** Factual Questions\ **Created:** [August 10, 2001, 2:52am UTC](https://boards.straightdope.com/t/please-help-120-v-appliances-on-100-v/75715 "2001-08-10T02:52:01Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![akitaking](https://avatars.discourse-cdn.com/v4/letter/a/e68b1a/32.png) [@akitaking](https://boards.straightdope.com/u/akitaking)\ **Post date:** [August 10, 2001, 2:52am UTC](https://boards.straightdope.com/t/please-help-120-v-appliances-on-100-v/75715/1 "2001-08-10T02:52:01Z")
Could anybody please tell me if video cameras and other electronic devices needing recharging from a country operating on 120 volts will work safely in Japan, where the standard is 100 volts? (Also, eastern Japan runs on 60 cycles and western Japan on 50 cycles. Is that important?) Does anybody have personal experience, good or bad, using appliances overseas? Thank you very much for your help! ---
**Author:** ![matt](https://avatars.discourse-cdn.com/v4/letter/m/a6a055/32.png) [@matt](https://boards.straightdope.com/u/matt)\ **Post date:** [August 11, 2001, 11:40am UTC](https://boards.straightdope.com/t/please-help-120-v-appliances-on-100-v/75715/2 "2001-08-11T11:40:20Z")
There’s many possibilities here. Firstly, if you’re using a wall plug DC supply provided by the manufacturer, it should have allowable input voltages written on it. Manuals also usually contain a specification page detailing the supply voltages required. You may find your video camera can operate with 100-120V supplies - it saves the manufacturer some hassle to build them that way since they can supply the same units to different countries. The supply frequency variation is unlikely to be important. Having said that, if this information isn’t available you _may_ still get away with it, but it could cost you the video camera to find out. There’s also a danger that it may appear to work for a while but the camera is in fact being damaged. Not recommended! [Technical blurb you probably won’t care about] Most of these things work as follows - a step down transformer takes the supply voltage and reduces it by a particular ratio. A bridge rectifier and capacitor turns this into rather wobbly DC. A regulator then converts this into clean DC at a lower voltage. This clean DC is used to recharge batteries and/or power the device. The problems come with the regulator step. If the regulator reduces the voltage by a considerable amount, it will work fine at the lower voltage and the device will never know the difference. If it doesn’t, you’ll be getting poorly regulated DC which may upset the various integrated circuits in the camera. [/technical blurb] ---
**Author:** ![Tedster](https://avatars.discourse-cdn.com/v4/letter/t/4491bb/32.png) [@Tedster](https://boards.straightdope.com/u/Tedster)\ **Post date:** [August 11, 2001, 2:57pm UTC](https://boards.straightdope.com/t/please-help-120-v-appliances-on-100-v/75715/3 "2001-08-11T14:57:20Z")
Electric clocks. With certain clocks that use 60hz as a reference standard, 50hz has the typical effect of making you late for work, since the clock is running slow. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [August 11, 2001, 3:06pm UTC](https://boards.straightdope.com/t/please-help-120-v-appliances-on-100-v/75715/4 "2001-08-11T15:06:26Z")
Perhaps you could buy an inexpensive volt meter and measure the output with a 100v input? ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [August 11, 2001, 3:21pm UTC](https://boards.straightdope.com/t/please-help-120-v-appliances-on-100-v/75715/5 "2001-08-11T15:21:33Z")
When I moved to Japan from the US I brought a few electronic devices, such as stereos, desktop computers and laptops. They work just fine. In fact, if you go to a cheap computer store in Japan, the power supply will say “115V” on the back - made in Korea and intended for export to the US, I’d guess. The frequency will only be important for appliances with big motors, e.g. washing machines and vacuum cleaners, as well as appliances that use the frequency for timing, such as clocks (as Tedster said) and simple mechanical timers like those built into toasters. Electronics with AC adapters almost never care about the frequency - the adapter usually outputs DC anyway. Also, look closely at the AC adapter for your electronics - most of them have the input voltage range written on it, and usually it includes 100V. Then you’ll know for sure that it’ll work. In fact, 100-240V is becoming common nowadays. ---
**Author:** ![sewalk](https://avatars.discourse-cdn.com/v4/letter/s/b3f665/32.png) [@sewalk](https://boards.straightdope.com/u/sewalk)\ **Post date:** [August 11, 2001, 10:45pm UTC](https://boards.straightdope.com/t/please-help-120-v-appliances-on-100-v/75715/6 "2001-08-11T22:45:25Z")
> [@](#): > > \*Originally posted by scr4 \* > **simple mechanical timers like those built into toasters.** Toasters work using thermostats. Frequency is not a problem. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [August 12, 2001, 2:01am UTC](https://boards.straightdope.com/t/please-help-120-v-appliances-on-100-v/75715/7 "2001-08-12T02:01:07Z")
> [@](#): > > Toasters work using thermostats. Frequency is not a problem. Oops. I guess I was thinking about toaster ovens with a dial to set the time, which I think are frequency dependent. Some cheap appliances in Japan (like my futon dryer) have two scales around the timer dial, one for 50Hz and the other for 60. ---
**Author:** ![CurtC](https://avatars.discourse-cdn.com/v4/letter/c/ce73a5/32.png) [@CurtC](https://boards.straightdope.com/u/CurtC)\ **Post date:** [August 12, 2001, 5:15am UTC](https://boards.straightdope.com/t/please-help-120-v-appliances-on-100-v/75715/8 "2001-08-12T05:15:19Z")
I had the impression that a digital electric clock (the standard kind nowadays, with a red LED display) would use the 60 Hz out of the wall for timekeeping. I recall seeing some info about how power companies now keep their frequency within a few cycles over months of time, so this would be _much_ better than using a local crystal oscillator. But I just checked with [howstuffworks.com](http://howstuffworks.com) (at [http://www.howstuffworks.com/digital-clock1.htm](http://www.howstuffworks.com/digital-clock1.htm) ), and he says: > [@](#): > > The signal can be extracted from the 60 hertz oscillations in a normal power line. Many clocks that get their power from a wall socket use this technique because it is cheap and easy. The 60 hertz signal on the power line is reasonably accurate for this purpose. > > The signal can be generated using a crystal oscillator. Obviously any battery-operated clock or wristwatch will use this technique instead. It takes more parts but is generally much more accurate. So which is it? I think that [howstuffworks.com](http://howstuffworks.com) blew this one.