With R10 = 4k3 and R21 = 220R we will have that output voltage. If, for example, lowest voltage measured across C1 when power supply is fully loaded is 27VDC then output of IC3 must be 25V. R10 and R21 set the output voltage of the regulator IC3 (LM317) and they must be calculated in such way that the output voltage is 2V lower than lowest input voltage. You must make some corrections in the schematic if the output voltage is lower or the voltage drop is higher when the current is high. The transformer must be 100-120W with 27-30VAC output voltage. The rectifier gets very hot when the output current is over 2A, so a small heatsink on top of it will be useful. We may use two or tree transistors in parallel with emitter resistors to achieve more power. Power transistor must dissipate quite a heat and thus require very big heatsink and maybe active cooling with a fan. After the final adjustment we may replace the trimmers with standart resistors. The trimmer P3 adjusts the minimum current limit. In the original schematic voltage reference is 9.4V so I chose to use two zeners - 3.3V and 6.2V connected in series which should give us 9.5V.Īlso the selected zeners have opposite temperature coefficients which should eliminate each other resulting in excellent temperature stability. This will give us stable reference voltage as the supply voltage is already regulated with LM317. I replaced unnecessary complicated circuit for voltage reference build with IC2 with simple resistor-zener circuit. After that I decided to simplify the schematic even further. I also made changes in the LED drive circuit and a few other minor changes. Consolidated dutchwest federal airtight manual. Recent blog posts with malware analysis of websites detected by online website scanner. Thesis Viola M´esza´ros Supervisors: P´eter Hajnal, University of Szeged Pavel Valtr, Charles University in Prague Doctoral School in Mathematics and Computer Science University of Szeged, Bolyai Institute Szeged, 2011. Generator klyuchej dlya das xentry.Įxtremal problems on planar point sets Ph.D. Thus total supply voltage for the opamps does not exceed 36V and therefor we may use standard ones. Circuits are calculated to produce 33V positive and 3V negative voltages. First of all I replaced two transistor-zener regulators with LM317L/LM337L. With the original schematic at hand I took the liberty to make a few changes. I found it here: There are scanned pages from the magazine with the original article and eagle files for the project. So, the previous article about lab power supply gathered quite a interest which is not a big surprise considering that there are over 200 pages of discussions in two topics about the schematic in this forum:! I think that the schematic in is not the original one but a modification of an older schematic published in a Czech electronic magazine.
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