Variable DC Power Supply Voltage range: 0.7 - 24V Current limiting range: 50mA - 2A Parts: P1:  500ohm Linear Potentiometer P2: 10Kohm Log. Potentiometer R1,R2: 2Kohm  1/2W Resistors R3:  330ohm  1/4W Resistor R4: 150ohm 1/4W Resistor R5: 1ohm 5W Resistor C1:  4700µF, 35V Electrolytic Capacitor C2:  4700µF,  63V Polyester Capacitor D1,D2: 1N5402 200V 3A Diodes D3:  5mm. Red LED Q1:  BC182  50V 100mA NPN Transistor Q2:  BD139  80V 1.5A  NPN Transistor Q3:  BC212  50V 100mA PNP Transistor Q4:  2N3055  60V 15A   NPN Transistor T1:  120V Primary, 36V Center-tapped Secondary 50VA Mains transformer PL1: Male Mains plug SW1: SPST Mains switch Notes: P1 sets the maximum output current you want to be delivered by the power supply at a given output voltage. P2 sets the output voltage and must be a logarithmic taper type, in order to obtain a more linear scale voltage indication. You can choose the Transformer on the grounds of maximum voltage and current output needed.  Best choices are: 36, 40 or 48V center-tapped and 50, 75, 80 or 100VA. Capacitor C1 can be 2200 to 6800µF, 35 to 50V. Q4 must be mounted on a good heatsink in order to withstand sustained output short-circuit. In some cases the rear panel of the metal box in which you will enclose the circuit can do the job. The 2N3055 transistor (Q4) can be replaced with the slightly less powerful TIP3055 type. http://www.reconnsworld.com/forum/read.php?13,184,184#msg-184 Sun, 19 May 2013 01:22:45 -0400 Phorum 5.2.9a http://www.reconnsworld.com/forum/read.php?13,184,337#msg-337 http://www.reconnsworld.com/forum/read.php?13,184,337#msg-337 able to come up with a polyester capacitor. Can a sub.
be made? Thanks]]> Bob Morrison Power Supplies Thu, 25 Aug 2005 12:35:01 -0400 http://www.reconnsworld.com/forum/read.php?13,184,298#msg-298 http://www.reconnsworld.com/forum/read.php?13,184,298#msg-298
Do you think yhat it is possible to use 48vac as input

best regards,]]> Cobus Power Supplies Wed, 25 May 2005 07:24:48 -0400 http://www.reconnsworld.com/forum/read.php?13,184,289#msg-289 http://www.reconnsworld.com/forum/read.php?13,184,289#msg-289 Andrew Power Supplies Fri, 06 May 2005 08:31:24 -0400 http://www.reconnsworld.com/forum/read.php?13,184,263#msg-263 http://www.reconnsworld.com/forum/read.php?13,184,263#msg-263 mailto:dbowlin@elmwood.k12.ar.us]]> David Bowlin Power Supplies Thu, 31 Mar 2005 13:01:03 -0500 http://www.reconnsworld.com/forum/read.php?13,184,186#msg-186 http://www.reconnsworld.com/forum/read.php?13,184,186#msg-186 Jay Power Supplies Fri, 07 May 2004 15:00:22 -0400 http://www.reconnsworld.com/forum/read.php?13,184,185#msg-185 http://www.reconnsworld.com/forum/read.php?13,184,185#msg-185 Jay Power Supplies Fri, 07 May 2004 14:57:58 -0400 http://www.reconnsworld.com/forum/read.php?13,184,184#msg-184 http://www.reconnsworld.com/forum/read.php?13,184,184#msg-184
Voltage range: 0.7 - 24V
Current limiting range: 50mA - 2A

Parts:

P1:  500ohm Linear Potentiometer
P2: 10Kohm Log. Potentiometer

R1,R2: 2Kohm  1/2W Resistors
R3:  330ohm  1/4W Resistor
R4: 150ohm 1/4W Resistor
R5: 1ohm 5W Resistor

C1:  4700µF, 35V Electrolytic Capacitor
C2:  4700µF,  63V Polyester Capacitor

D1,D2: 1N5402 200V 3A Diodes
D3:  5mm. Red LED

Q1:  BC182  50V 100mA NPN Transistor
Q2:  BD139  80V 1.5A  NPN Transistor
Q3:  BC212  50V 100mA PNP Transistor
Q4:  2N3055  60V 15A   NPN Transistor

T1:  120V Primary, 36V Center-tapped Secondary 50VA Mains transformer

PL1: Male Mains plug
SW1: SPST Mains switch

Notes:

P1 sets the maximum output current you want to be delivered by the power supply at a given output voltage.
P2 sets the output voltage and must be a logarithmic taper type, in order to obtain a more linear scale voltage indication.

You can choose the Transformer on the grounds of maximum voltage and current output needed.  Best choices are: 36, 40 or 48V center-tapped and 50, 75, 80 or 100VA.

Capacitor C1 can be 2200 to 6800µF, 35 to 50V.

Q4 must be mounted on a good heatsink in order to withstand sustained output short-circuit. In some cases the rear panel of the metal box in which you will enclose the circuit can do the job.

The 2N3055 transistor (Q4) can be replaced with the slightly less powerful TIP3055 type. ]]> Jay Power Supplies Fri, 07 May 2004 14:54:17 -0400