HarryA

I do not see your question; perhaps I am missing something

If you are not big on building your own transformer look at: http://www.surplussales.com/homenew.html#Transformers example; 95VA Toroidal Transformer 117/234V to 2 x 15V or 30V at 3.2 Amps at 230 v that would give you say: 14.7 volts; a fat resistor would remove the 0.7

if: Vp = primary voltage, Ip =primary current, Np = number of primary windings. Vs = secondary voltage, Is = secondary current, Ns = number of secondary winding. then: Vp = Vs(Ns/Np) and Ip = Is(Ns/Np) example: To transform 120 vac to 12 vac, Vs = 120 vac (100/1000) = 12 vac Ns/Np = 0.1, say 100/1000 Using Ip = Is(Ns/Np) I am not clear which way you are going here. 0.3 amperes = 1 ampere (Ns/Np) Ns/Np = 0.3 say 180/600 or: 1 ampere = 0.3(Np/Ns) Np/Ns = 3.33.. or say 600/180 For power: Pp = Ps at 100% efficiency. Ps = n * Pp where n is the efficiency factor. n between 65 and 99 percent For 50 watts at the secondary and 75% efficiency the primary power would be: Pp watts= Ps/n = 50 vac/0.75 = 66.66... watts. For Impedance: Zp = Zs(Np/Ns)^2 To connect an 8 ohm speaker to a 400 ohm amplifier: Np/Ns = (Zp/Zs)^0.5 = (400/8)^0.5 = 7 I must confess I have no idea how many windings real transformers have; do not go by my numbers. Somewhere I have a book that has information on designing transformers if you need more info I will try to find it.

I would think if the larger rated relays failed then the smaller rated relays would not last as long. Have you tried looking on Ebay for replacements? I have had good luck recently finding replacement parts on Ebay. Sorry I can not be more helpful to you; good luck.

At the lower left the component would be a 1500/1k5 resistor like the one at the lower right. The LEDs indicate which coil/output is active. At the upper right the symbol looks like a ground off the signal generator. The LEDs are represented by the white dots on the front panel above the words OUT perhaps? P1 and P2 look odd; they have the potential of shorting the inputs. At P2 with the wiper all the way down the input would be shorted circuited.

I used: bluetooth camera for iphone also see: https://techpp.com/2013/04/17/bluetooth-cameras-connect-smartphone/

Perhaps? To big? " This Fujifilm FinePix digital camera has Bluetooth connectivity for wireless media transfer. " https://www.bestbuy.com/site/fujifilm-finepix-xp130-16-4-megapixel-digital-camera-sky-blue/6204739.p?skuId=6204739

If you do not need SMD perhaps "The LT138A/LT338A (LM138/LM338) series of adjustable regulators provide 5A output current over an output voltage range of 1.2V to 32V." The LM338 is about 1$ each on ebay.

Search on ebay for "personal alarm switch" most do not have a switch just a pin you pull out. I used one to find the blockage in a drain pipe. They are LOUD!

Power Strip with USB, Surge Protector Smart 3 Outlet and 4 USB Port Charger with 5ft Extension Power Cord 1250W 100-240V https://www.amazon.com/Protector-Extension-100-240V-Portable-Transformers/dp/B07KGPFHYC/ref=sr_1_9?s=electronics&ie=UTF8&qid=1548959567&sr=1-9&keywords=surge+protectors+for+computers I worked with a power supply that was 900 amperes and 8 volts; this would not work for that

This maybe helpful: How to make an IR blaster: https://www.instructables.com/id/How-to-Make-an-IR-Blaster/ and an amplifier https://www.amazon.com/Geekroom-Headphone-Amplifier-Rechargable-Computers-Black/dp/B07F1JS4JV/ref=sr_1_21?ie=UTF8&qid=1548463071&sr=8-21&keywords=cell+phone+audio+amplifier This is an old question but it maybe helpful to someone in the future.

audioguru is correct. But if you are interested in cell phones you may find this site helpful: https://www.instructables.com/id/Make-your-own-cellphone-from-scratch/

I would use an arduino microcomputer with an arduino display shield for the display. The best microcomputers are about 22$ down to a few dollars for the ones from China. The arduino display shields are around 10$ or so. The Utlransonic distance measuring transducer senors are less than 10$; they detect if you are in your seat or not. https://www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias%3Daps&field-keywords=arduino+uno https://www.amazon.com/s/ref=nb_sb_ss_i_1_13?url=search-alias%3Daps&field-keywords=arduino+ping+sensor&sprefix=arduino+ping+%2Caps%2C215&crid=DDBCCF7NH7CK https://www.amazon.com/s/?ie=UTF8&keywords=arduino+display+shield&tag=geminipcstand-20&index=aps&hvadid=28314448797&hvqmt=e&hvbmt=e&hvdev=c&ref=pd_sl_83ujuhent2_e

One can go from 50hz ac to 12 vdc via battery charger then from 12 vdc battery to 60hz 120v via a dc to ac converter. see: https://www.bing.com/videos/search?q=50hz+to+60hz+converter&&view=detail&mid=3D9219028DABBB0162A53D9219028DABBB0162A5&&FORM=VDRVRV&ajf=60

using "the GIMP"

Hello, I would think few of us would know anything about mig welders. I gather you want to hot switch the current from the mains to the welder. What current does your welder draw would be a start. You may need a high current relay to do the switching. Like? https://www.grainger.com/product/5ZH38?cm_mmc=PPC:+Google+PLA&s_kwcid=AL!2966!3!166591437759!!!g!81032003877!&ef_id=WqqIQwAAAacd4m57:20180315145043:s It's rated "AC contract rating - relay: 25 amperes at 240 volts ac." You need a relay rated higher than it draws off the mains because of the inductive load - I gather the mig welders have a transformer at the input like an arc welder?

How about 3 terminal adjustable voltage regulators? see for example: https://www.mouser.com/ProductDetail/ON-Semiconductor-Fairchild/LM317AHVT?qs=%2fha2pyFadugRpOCsw7uJG%2fYkcWjLe5SQfHkipQZSRvGAuHf8Q8Z20lpgQCwyK1vllMxUP7WNhWIGj0RAnAK1dQ%3d%3d 60 volts max and 1.5 amperes. Poke around at Mouser for higher current ones also. There are filters on their site that are helpful.

Your " unknown phone " is unknown to us also. One photo is worth a thousand words, two photos are worth two thousand words, etc

You need to define this so someone can help you.

The power required by the charger would be in the order of: 120 * 0.3 = 36 watts. The 220/240 To 110/120 Volt European Socket Power Converter Step Down Transformer off ebay.com are rated 100 watts and not expensive. Order one directly from China; it's just up the big pond from you

I enlarged the image off the Amazon.com but could not read it https://www.amazon.com/Black-Decker-LCS1620-Lithium-battery/dp/B01M6TQPY2/ref=sr_1_3/141-0275392-4037060?ie=UTF8&qid=1499813460&sr=8-3&keywords=Black+%26+Decker+LCS1620 ...but ebay.com has a readable image http://www.ebay.com/itm/Black-Decker-LCS1620-20v-20-Volt-Lithum-Ion-Battery-Charger-NEW-/272090041874?epid=1640405275&hash=item3f59d48e12:g:mf8AAOSwawpXr3eh 120v @60hz 300ma

" which one is right? " What two are you comparing?

This unit will work stand alone (with out a UNO) and has wifi> https://www.amazon.com/HiLetgo-Version-NodeMCU-Internet-Development/dp/B010O1G1ES/ref=sr_1_22/136-5999016-8336545?ie=UTF8&qid=1496770085&sr=8-22-spons&keywords=arduino+wifi&psc=1 Read the Q/A section.

If you search on amazon.com for "arduino wearables" you will find a number of devices. There are also a number of books on the subject.

I gather if you want 1.8 volts out you buy the LP3853ET-1.8/NOPB and if you want say 2.5 volts you buy the the LP3853ET-2.5/NOPB chip and so forth. They must define the input voltages for each somewhere? What do you mean by "Can I use LP3856 here ?" ? What is your application?