Simple DIY 12V to 220V AC Inverter Project Using 4 Transistors. Does it work?

Comments · 24

• KA

  @karlsangree · 2 years ago

  "It didn't blow up, that's a good sign." The words of many an intrepid experimenter. 😃

  1

• TW

  @twithheldmwithheld8938 · 2 years ago

  Love these videos. And I can't help but be very impressed with your transistor tray. Something I struggle with is organizing items like this. Maybe a video someday on how you organize your shop, as I am sure you have a ton more than I do, and it all seems in 'place'. 😁

  3

• AL

  @alexyurchenko3569 · 1 year ago

  Please show how you organize your parts. The transistor bags are really nice.

• RA

  @ralphj4012 · 2 years ago

  You may be able to create something akin to a sine wave (from that square wave astable) by using RC filters (1k and 0.1uF or something) in the base drives, perhaps between the junctions of the 220Rs and 330Rs.

  1

• DU

  @Dutch_off_grid_homesteading · 2 years ago

  Heya, that is a nice DIY pcb project. but I really miss is the polaritie protection on the 12 Volts

• GE

  @gendragongfly · 2 years ago

  I think you should try with a lower wattage lightbulb. If this super basic inverter can provide 50 watts I'll be very impressed. Maybe start at 10 watts and work your way up while checking if the output voltage doesn't drop below 220v 🙂

• CA

  @CaseVerrijst · 2 years ago (edited)

  I was wundering. To test the capabilities of the transformer on 50Hz. Can’t you take a 230 to 12 or 15V ac transformer, with sufficient amps available and then check wat the output wil be. So you know wether it is the circuit or the transformer causing the voltage drop from 240 to 120v

• ST

  @steves8083 · 2 years ago

  Hi Richard,<br><br>Looking at the schematic alone, it very much seems as if the circuit is illogical and badly designed. Does the schematic match the PCB? Q3 and Q4 appear to have their collector and base connections REVERSED!<br><br>With the circuit as shown, the MOSFET gate drives come from the multivibrator transistors&apos; base connections. This means two things: Firstly, the base voltage pulses cannot exceed around 0.6V to 0.7V above ground and secondly, the base current pulses for Q3 and Q4 (2SC1815), exceed the manufacturer&apos;s absolute maximum rating of 50mA. The peak base current is calculated as (VCC - 0.6) / 220 ohms. So, for a maximum base current of 50mA,the supply voltage must not exceed 11.6VDC!<br><br>I would change the circuit by reversing the base and collector connections to Q3 and Q4. R1 and R5 (now the base pull-up resistors), I would increase from 1K to 2.2K each. This will result in a higher gate drive voltage. Then reduce the capacitor values to set the desired frequency which will be somewhat lower with these changes. Check that the capacitors, if electrolytics, have their positive sides connected to the transistor collectors. If it is necessary to use trimpots for fine frequency adjustment, place these in series with R1 and R5 each at around 2K. Ensure they are adjusted for waveform symmetry on the MOSFET gates.<br><br>Once the correct frequency has been established, the MOSFETS are much more likely to saturate because their gates are being driven by larger pulses, which is necessary to get a good switching current in the transformer primary (12V side). This improves efficiency and reduces dissipation in the MOSFETS.<br><br>It could also be useful to place an electrolytic of around 100uF / 25V between Vcc and ground on the PCB especially if long wires are used to connect to a PSU.<br><br>Once working properly, this will be a useful project!<br>Regards Steve in UK.

  3

• NA

  @naeemhaq3504 · 2 years ago

  100 years old circuit

• GO

  @gorky_vk · 2 years ago

  That&apos;s rip-off of old Chinese car inverters back in the time when every mobile phone had different charger connector so it was easier to have one of these so everyone can plug their own charger into it. Output power is low, even sellers from ebay back then didn&apos;t claimed more than 10-20W and product had much smaller transformer of course.

• MA

  @maks886 · 2 years ago

  I never could understand why is there such huge demand for these 220V inverter projects online. Most of them shown by people in some 3rd world countries. Not to judge, but is it really so much harder to get mains power than to get a battery, mosfets, resistors, pcb, a transformer etc? These basic inverters have so much flaws, they never give a stable 50Hz output, never deliver on the promised power rating, the efficiency is horrible, the ripples on the output are HUGE and dangerous to you and to most electronic equipment. To give 100W at the output from a 12V battery, &nbsp;the current through the primary would have to be like 20 A or more, which will never happen with 0 cooling. This circuit is only good for one thing, and it&apos;s powering a light bulb very inefficiently. So popular though, I don&apos;t get it! The only scenario I see it useful is the one presented here - for education and out of curiosity.

  5

• CH

  @chrishartley1210 · 2 years ago (edited)

  <a href="https://www.youtube.com/watch?v=She4z7fTToQ&amp;t=540">9:00</a> Prediction, input=15VDC, output=140VAC.<br>Let&apos;s see how close I am.<br>Edit: wasn&apos;t a bad guess, you didn&apos;t allow for the fact that since the 15V output was AC, the peak would be about 26V. Reversing that, your peak input needs to be 26V not 15V.