Capacitor problem Answered

I needed a 2.2 and a 10 uf capacitor to make a metal detector, but the values printed on my capacitors are not less than 5. I want to find that if the values on the capacitors are in uf, nf or pf. And if they are none of them. 

Question by tanyutsharma   |  last reply


What value (pF/uF) this capacitor? Answered

It's blue, it has a brown blob on the side, a small grey and a small brown spot on the top.I've not been able to find a reference to this colour code, does anyone know how to read it?L

Question by lemonie   |  last reply



How do I find the secondary current of a DRSSTC Tesla Coil?

I need to know the secondary current to determine what turns value to use for a feedback current transformer in the driver circuit.  The secondary capacitance, if that has anything to do with this, is 6.9424 pF.

Question by UbuntuNinja   |  last reply


Is there any way I could put custom firmware on my digital photo frame? Or any other hacks!?

I have a matsui pf-a701w eg: -View a webcam ( via usb ) -Play gifs -play videos -have custom firmware -and any other cool stuff you guys might know about!

Topic by poparoo4   |  last reply


Low power mosfet replacement problem

Can anyone help me identify a substitute for a mosfet? It is used, as far as I can tell, as a low power DC switch. It is a 6 legged SMD beastie, part number FDC654 - possibly with a P on the end and is completely short circuit. I'm assuming I've got the right device. There is some information about it here: http://www.fairchildsemi.com/pf/FD/FDC654P.html I can't find anywhere to buy this component as an amateur, and don't know enough to work out a suitable replacement. Can anyone help?

Question by throbscottle   |  last reply


Can I power a 5M 5050 RGB led strip with a pc PSU?

I would love to control an RGB led strip with an Arduino, it would look great on my desk. I would love to know wether I could power this strip using an old desktop powersupply. LED strip: http://www.ebay.com/itm/5M-5050-RGB-SMD-Non-Waterproof-Flexible-LED-Strip-300LEDs-Free-44Key-IR-Remote-/131705042790?hash=item1eaa3b7766:g:RmYAAOSwX~dWnaxL#shpCntId PSU: http://www.bitzotech.com/fsp-group-fsp280-60pna-e-pf-280-watt-power-supply-3659-164-p.asp I want to be able to either power the strip directly and control it with an arduino using a mosfet, or plug it in to the box to control the colours with the ir remote that comes with the strip. I probably won't use the entire strip at once, but I think I'll use 3M or less. It would be great if you could help me!

Question by FlorianS20   |  last reply


My First Tesla Coil!

I just made my first tesla coil, it stands only about 6 inches tall and has a diameter of ~1". The tank capacitence is ~940 pF. The wire gauge is 30. The topload is 6 inches in diamerer and 1 inch tall. the power supply is a 7.5kv, 60mA NST with a terry filter. It's a static spark gap. The primary has 13 turns of 14 gauge wire, it's a 30 degree cone.It gives out nice arcs and cornea. I will post photos and video soon, as my workshop reeks of ozone right now.I can probably get better preformance with using thicker (or no) aligator clips (prototype stage right now) and if I change the primary. The wire got too hard to turn, so near the center there's like 2" of leeway on all sides of the secondary... sorry about sound quality in the videothe rod in the video is kinda grounded. The rod you see is a thin copper pipe taped to a 3 foot, 1/4 inch thick dowel rod that I'm holding onto.

Topic by guyfrom7up   |  last reply


Power supply problems for my project

Hi everyone. I'm stuck with power supply problems in my project. My project is a drink dispenser (cocktail machine) with water level indicators. I was thinking of putting 4 water pumps connected to relay modules, controlled by Arduino or microcontroller (something like attiny). The microcontroller would receive a command with 2 push buttons (tasters) and depending on the button pressed, it would combine 2 liquids from 2 tanks into one glass. Now, the code isn't a problem. I need to add a liquid level indicator to the circuit (4 indicator circuits for 4 liquid tanks). Now, the pump I was thinking of buying is rated 5V and the current draw is about 150-250 mA. Attiny2313 operates on 2.7V-5.5V. I found the water level indicator circuit also rated 5V ("https://www.electronicshub.org/water-level-alarm-using-555-timer/" but I was thinking about the one without 555 timer). Now, my question is, what is the best way to power all these components. I was thinking about getting a 220V to 5V 2A PSU adapter ("https://www.ebay.com/itm/AC-110V-220V-TO-DC-5V-12V-24V-Switch-Power-Supply-Driver-Adapter-LED-Strip-Light/152134115704?hash=item236be66178:m:mnohYz4NZlT_Dq5l5lWNUMg:rk:1:pf:0"). Will that be enough and will it destroy any of my components. Thanks in advance!

Topic by Kvragu 


EMP notworking,i followed every steps on tutorial. Can you find where goes wrong? Answered

Tutorial i follow: http://teslaundmehr.de/2015/12/05/emp-jammer/   Componet : single 18650 battery 3v to 40v boost convert  1.2mm coil 2sc2078 transistor 47 and 220 pf capacitor 10k resistor i can hear some weak sparkish noise from top of the coil, and transistor goes hot too. but just nothing happens to lightbulb and calculator April 18 update: i connected the losing end( pic10). but still nothing, any other thought ? new diagram at pic 8 i'll keep updating as i soldering componets using no wire April 22 update: it worked, with a other small test coil i made, (pic 1,3,4)i swaped several transistors made sure only problem was the coil. where goes wrong with the bigger coil (pic2,5) ?  also, i've switched winding lead on big coil, still goes nothing (small one works with either way). i was guessing perhaps i've made too many turns on L1 somehow changed behavior of coil (another interesting phenonenal i've noticed is as you stick an iron cord inside coil, EMP field despairing rapidly to 0. which is bit different then i learned in high school)

Question by EthanY   |  last reply


building a HD Audio front panel for my PC. Audio circuit?

Hi! I have problem with my computer. the motherboard has HD-Audio but the front panel is the usual AC97 standard. You can change the BIOS config so the front panel audio connector acts as an AC97 one, but then the problem is the speakers connected to the back keep playing even if you connect a set of headphones to the front panel. The reason is the audio jacks used for HD-audio are different from regular jack connectors (and very rare to find!). While the insertion of the plug in a regular jack connector results in breaking a circuit (and so, physically muting the loudspeakers), in an HD Audio jack, the insertion of the plug results in closing a switch (sending a signal to the driver ordering to mute the speakers by software). I managed to create a sort of HD audio Jack by combining a regular jack connector and a zero pressure micro-switch so when the plug enters the hole, a tip inside the hole closes the micro-switch. I wanted to make a good quality front panel so instead of just wiring the jack connectors (and micro-switches) to the cable, I decided to add an EMI filter. I took the circuit from this doc: http://www.formfactors.org/developer/specs/A2928604-005.pdf and more precisely from fig 6 at page 25. The circuit uses two 220 pF capacitors and two inductors for each jack connector. In this aspect the circuit is identical to that proposed for AC97. The problem is I have no idea what inductors to use or how to ask for them at the shop. All the diagram says in a footnote is: ZL should be 600 Ohms or greater @ 100MHz with a low Q (broad Impedance curve over frequency) but not even the guys at the shop knew what piece to give me. So what I did was to cannibalize the inductors from two cheap promotional radio receivers with jack connectors for the headphones and use them for my circuit. After all, they perform the same function: filter the audio signal at the headphone connector so I supposed they should have the correct values I needed. But my circuit is very noisy! headphones have a constant electronic background noise (that seems to react to things like mouse movements, hard disk activity or whiteness of the screen) and microphone has a lot of noise (of course I'm using very good quality mic+headphone). The cables are audio cables for front panel audio so they are supposed to be correctly shielded so the problem is in the circuit at my custom board. I would like to make a tutorial (including HD Audio connector construction) once the front panel is working properly but I don't know how to fix it. Any ideas?

Topic by jedikalimero 


building a HD Audio front panel for my PC. Audio circuit? Answered

Hi! I have a problem with my computer. the motherboard has HD-Audio but the front panel is the usual AC97 standard. You can change the BIOS config so the front panel audio connector acts as an AC97 one, but then the problem is the speakers connected to the back keep playing even if you connect a set of headphones to the front panel. The reason is the audio jacks used for HD-audio are different from regular jack connectors (and very rare to find!). While the insertion of the plug in a regular jack connector results in breaking a circuit (and so, physically muting the loudspeakers), in an HD Audio jack, the insertion of the plug results in closing a switch (sending a signal to the driver ordering to mute the speakers by software). Since I can't find this kind of jacks anywhere, I managed to create a sort of HD audio Jack by combining a regular jack connector and a zero pressure micro-switch so when the plug enters the hole, a tip inside the hole closes the micro-switch. I wanted to make a good quality front panel so instead of just wiring the jack connectors (and micro-switches) to the cable, I decided to add an EMI filter. I took the circuit from this doc: http://www.formfactors.org/developer/specs/A2928604-005.pdf and more precisely from fig 6 at page 25. The circuit uses two 220 pF capacitors and two inductors for each jack connector. In this aspect the circuit is identical to that proposed for AC97. The problem is I have no idea what inductors to use or how to ask for them at the shop. All the diagram says in a footnote is: ZL should be 600 Ohms or greater @ 100MHz with a low Q (broad Impedance curve over frequency) but not even the guys at the shop knew what piece to give me. So what I did was to cannibalize the inductors from two cheap promotional radio receivers with jack connectors for the headphones and use them for my circuit. After all, they perform the same function: filter the audio signal at the headphone connector so I supposed they should have the correct values I needed. But my circuit is very noisy! headphones have a constant electronic background noise (that seems to react to things like mouse movements, hard disk activity or whiteness of the screen) and microphone has a lot of noise (of course I'm using very good quality mic+headphone). The cables are audio cables for front panel audio so they are supposed to be correctly shielded so the problem is in the circuit at my custom board. I would like to make a tutorial (including HD Audio connector construction) once the front panel is working properly but I don't know how to fix it. Any ideas?

Question by jedikalimero   |  last reply