6 ms·
Transistor Wall Clock
- baxter001 11y agoAn interesting point would be that frequency of the AC power line is used for timing, what's more your supplier will generally try to normalize the frequency http://www2.nationalgrid.com/uk/Industry-information/electricity-transmission-operational-data/ http://www2.nationalgrid.com/uk/Industry-information/electri... if if they're alternating too fast they'll slow it down to compensate and give an accurate long-term average. I wonder if home-solar converters have this feature built in :)
- tcas 11y agoHome solar converters will need to synchronize to the mains power supply like any generator before connecting. The power supply capacity of the grid is orders of magnitude more powerful, so connecting it out of sync will still cause it to sync, however, it most likely won't be pretty. Once it's connected, the grid will force it to stay in sync. Here's a video of a generator who's synchronization system is being "hacked": https://www.youtube.com/watch?v=fJyWngDco3g https://www.youtube.com/watch?v=fJyWngDco3g Although the article doesn't mention it in specific, that's what the comments say is happening.
- amelius 11y agoThat's a lot of resistors. Makes me wonder about the power consumption.
- klodolph 11y agoProbably not very much power. Diode transistor logic with 10k and 100k resistors in a 9V circuit, worst case you're looking at about 1 mW per resistor. I suspect LED driving current dominates the power consumption of the device.
- IvyMike 11y agoThe manual (http://www.transistorclock.com/tranmanual.pdf http://www.transistorclock.com/tranmanual.pdf ) has the spec. Answer: 5.7 Watts.
- amelius 11y agoThat is quite a lot. The table in [1] shows that an average 9V battery has a capacity of about 3.5Wh, meaning you can use this calculator for a little over half an hour on a single battery. [1] http://www.zbattery.com/zbattery/batteryinfo.html http://www.zbattery.com/zbattery/batteryinfo.html
- unwind 11y agoThe product is called "transistor clock". It's a clock, for wall hanging, it's not a calculator and the images on the page of TFA show a power cable.
- ganeumann 11y agoJust don't bring it to school with you.
- excitom 11y agoHaha, came here to say that, you beat me to it.
- Houshalter 11y agoJust don't make it look like a bomb on purpose, and take it out during English class, and then plug it in and set the alarm off.
- listic 11y agoI guess it only counts time right with the (US) 60 Hz power supply? Then, it's strange that they made it show time in 24-hour format.
- cbd1984 11y agoA lot of Americans use the 24-hour format by default.
- sneak 11y agoEngineers generally use 24h time and SI everywhere on Earth (at least when engineering), regardless of local customs.
- kens 11y agoAccording to the website, you can just change a couple wires and it will work with 50 Hz power. This changes the divide-by-6 circuit to divide-by-5. http://www.transistorclock.com/50Hzmod.pdf http://www.transistorclock.com/50Hzmod.pdf
- dperfect 11y agoSimilar project: http://techno-logic-art.com/clock.htm http://techno-logic-art.com/clock.htm
- jack-r-abbit 11y agoI've seen that one before. Truly an amazing work of art.
- AndrewKemendo 11y agoWould be cool to have a similarly exploded IC version next to it.
- jccooper 11y agoThey have that: http://www.ttlclock.com/ http://www.ttlclock.com/
- deleted 11y ago[deleted]
- huangc10 11y agoThis is so cool. As an Electrical Engineer turned Software Engineer, this makes me miss working with hardware :(.
- pthreads 11y agoI am just curious is it not be possible to use a crystal oscillator and hence not be dependent on the power line for timing? Are they not doing it just on principle i.e using only transistors, resistors, diodes and capacitors? I vaguely remember building an AM transmitter in high school using a crystal oscillator and transistors but no ICs.
- kens 11y agoYou could use a crystal oscillator, but you'd need a bunch of circuitry to divide the frequency down to 1 Hz. The lowest-frequency crystal I could find is 20kHz. In other words, it's a lot easier to start with 60Hz than 20kHz when you're using individual transistors.
- dynode 11y agoIt's not that bad.. typically you use a 32.768kHz ("watch") crystal then divide by 15 to get one second. You can do it with two chips (a bunch of solutions, one is two 7468).
- javawizard 11y agoAnd how many transistors does that translate to?
- kayfox 11y agoProbably 30, but you dont need existing transistors needed to divide 60hz down to 1hz, so the change in parts count might be smaller. Edit: Previously said 30, but it looks like its 60. Each JK flip flop takes 4 transistors. Edit: Back to 30, the bistable circuit in the clock uses two transistors each.
- pps43 11y agoYou need 15 triggers to go from 32768 Hz to 1 Hz. Existing circuit uses 4 triggers to divide 60 Hz by 10 and another 3 to divide by 6. You can repurpose those so you only need 8 extra triggers. Two transistors each means 16. You can also save 6 transistors from existing dividers because all divisions are by 2. So net total is 10 extra transistors for division, plus at least one in the oscillator itself.
- IvyMike 11y agoI purchased and assembled this kit. It was fun, although it's pretty time consuming. Do you want to get better at soldering? You'll get better at soldering. In fact, if your kit works, you'll have made 2700 good solder joints.
- timonoko 11y agoWhere is the vacuum tube version? I have always wondered if is possible to make complex vacuum tube logic circuitry just by hand in one big container and suck the air out. In this case in a glass container because you want those glowing clock numbers to show.