noz-25
LEDadict
For most of my project with LED diodes i use small power supply unit.That power is rarely over 20-30W!Until now i use every time linear power supply with current driver LM317 for power to 20W.Over that i use to buy small SMPS like this one:
This is chinese SMPS 36W.It use chip-rail CR6850 and two transistors.Here in my place it cost 14e (18,50$)!It's not cheap as You can see.So i would like to make few small power SMPS.Second thing i want to show You is "electronic transformer for halogen lamp".It is SMPS with two transistors BLD128,EMI filter,output is NOT rectifier so it's 12Vac and power is 105Watt.Manufacturer is OSRAM.I try it with 3 bulbs with 35Watt each and works smooth.I have 7-8 pcs of this but i can't use them with LED.Problem is MINIMUM LOAD,without that it's just don't work at all.When You turn on AC if there is no load and try to measure voltage-there is nothing on output,You MUST to connect minimum one bulb 20watts to start working.Then it's no problem to parallel put rectifier and LED.I ask MANY people and search all over the net but i can't find the solution for minimum load.This shematic here is not original but principle is same.I would like to change something,add,remove or what ever is need to make this SMPS to oscillate.If You think that is not possible then i need some shematic of low power SMPS with bipolar transistors so i can use this transistors,transformer(rewind it of course) and other part's,becouse i don't need halogen ballast.
On shematic You can see output stage which is made excatly for this problem.It should be solution but it's not work for me.Value is:for RC-12R 1W,33nF;DR1 is 10uH;C4 is 1000uF,diodes shotky.
How i can find out which transformer core is this?It's small but it can take 100watt without problem so it's perfect for me!And on secundary side it has 8turns for 12V so it's not so high frequencyEvery help,comments,critics are very,very welcome!!!I am sure there is lot of You who also need small power SMPS for different app.Small amps,preamps,equilaisers,lighting.....
This is chinese SMPS 36W.It use chip-rail CR6850 and two transistors.Here in my place it cost 14e (18,50$)!It's not cheap as You can see.So i would like to make few small power SMPS.Second thing i want to show You is "electronic transformer for halogen lamp".It is SMPS with two transistors BLD128,EMI filter,output is NOT rectifier so it's 12Vac and power is 105Watt.Manufacturer is OSRAM.I try it with 3 bulbs with 35Watt each and works smooth.I have 7-8 pcs of this but i can't use them with LED.Problem is MINIMUM LOAD,without that it's just don't work at all.When You turn on AC if there is no load and try to measure voltage-there is nothing on output,You MUST to connect minimum one bulb 20watts to start working.Then it's no problem to parallel put rectifier and LED.I ask MANY people and search all over the net but i can't find the solution for minimum load.This shematic here is not original but principle is same.I would like to change something,add,remove or what ever is need to make this SMPS to oscillate.If You think that is not possible then i need some shematic of low power SMPS with bipolar transistors so i can use this transistors,transformer(rewind it of course) and other part's,becouse i don't need halogen ballast.
On shematic You can see output stage which is made excatly for this problem.It should be solution but it's not work for me.Value is:for RC-12R 1W,33nF;DR1 is 10uH;C4 is 1000uF,diodes shotky.
How i can find out which transformer core is this?It's small but it can take 100watt without problem so it's perfect for me!And on secundary side it has 8turns for 12V so it's not so high frequencyEvery help,comments,critics are very,very welcome!!!I am sure there is lot of You who also need small power SMPS for different app.Small amps,preamps,equilaisers,lighting.....
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