simple switching power supply

Very good design :-) compact and with solid self oscillating mechanism (means no strange meta states that looks like device was not sure about what to do next hehe) i have one question cuz i think one spect could be troublesome. I hav in mind an op-amp and precisely i think there will be problems in buying cheap and easy achievable model that will match operating frequency. For example old but still popular LM741 has maximum frequency response up to 10khz :/ other like LM358DP are also not better having maybe around 20khz. Audio oones are up to 30-40khz because as audio ones it is even good to have such limit. Ofcoz there are many possible models with superb frequency response up to mHz range but they are costly and frequently require to waste time searching online shops for a one and most painfull aspect of such case means delay due to delivery and frequently by not so fast realized buy order. Electronics parts stores do not have such problems but frequently do not posses specialized chips by now and also we are forced to place order :( ...actually i will want to ask if not better option is use discrete transistor equivalent or most superb option uses a digital circuit using for example CD4xxx cmos chips??

Yes it's nice ! Wouldn't it be more a pwm ? I did something along similar lines were a pulse reg maintains a couple of volts across output linear regulator keeping dissipation low at high amps. I never got around to finalising it it just needs an oscillator as it's currently using the inbuilt one so never published kept meaning to get back to it but never did. It's called '' Differential 2 - copy '' even the title is unfinished. It's all discreets as i think the opamp's in E.c are a joke for all but the most basic tasks. So well done for using one.

And I forgot to mention it's great to see you using your own designs. I look forward to seeing how you develop your circuits on here. Really well done thanks for sharing!

That's cool it's your own design. I'm still learning how and why components relate to and interact with each other- and it's increasingly apparent to me that's a very deep rabbit hole lol. Anyhow, it's my (and I would think every beginner's) goal to have enough understanding to design my own circuits. So, good job.. :^)

WWW.tme.eu is where o buy my parts

If you have issue with searching for high freq. op amp and if you can copy with whistling from PS, you can multiply capacitor on base of transistor. Ill remake circuit to hold frequency and look more like PWM and let you know ASAP.́ Thanx anyway for comments ^.^

!!! Surprise .... an LM358N a whole megahertz O.O . I must look into datasheets cuz i was certain about those have max a 100khz in best version. I remember clearly when i search for preamp to amplify double saw waveform (i experimented with simple monosynth construction similar to cult TB303 . And remember also how i try 2 opamps and when take output on scope "a god of poor things" sent me image of poor performance and vast feel of disappointing . Around 10kcps those silicon wonders start lose tracking of input wave and after a one more kcps added a shame lame mutated trniagle'o'sine deformed thingy that frighten all kids in vicinity appear on scope and very bad language start to emanate to anyone in area. I rather rarely use opamps most things doing from discretes and i was unaware of such limitation. I test 2 opamps with similar reasons. And the second one wa 358dp so this need investigation cuz i know that i somewhere have bunch of those amps scavenged from some electro-junk.

It needs to be remembered that an opamp that says 1mghz bandwidth is at unity gain and if you apply even a modest amount of gain let's say ×10 the bandwidth is reduced by that amount so 1mghz becomes 100khz and this is best case as the 1mghz will in all likelihood be a typical performance spec.

And also that a lot of opamp's ain't unity gain stable and so 1mghz becomes meaningless for the most part as we would have to apply gains in excess of ×10 in order to stabilise the circuit. There are techniques to get around this disability and there are opamp's that have internal compensation but they have even lower bandwidth.

Its true, as I remember at 1MHz gain is 1:1. I have lowered frequency spam to 40-80kHz. Feel free to ask, many thanx for support. ^.^