Power Supply Adapter

Component parts list: P1____________500R Linear Potentiometer P2_____________10K Log. Potentiometer R1,R2___________2K2 1/2W Resistors R3____________330R 1/4W Resistor R4____________150R 1/4W Resistor R5______________1R 5W Resistor C1___________3300µF 35V Electrolytic Capacitor (see Notes) C2______________1µF 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_____________220V 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. Yo...

Here a variable power supply circuit which the output voltage can be adjusted. The stabilizer IC may be changed with different value as needed, example 7815 for 15v maximum voltage. Component Parts List: T1 Transformer 10:1 Secondary 24V @ 2A BR1 Bridge Rectifier 50V PIV 2A rating C1 4700u (35V) C2 0.001u C3 2200u (35V) C4 0.001u C5 4.7u (25) C6 0.01u R1 10k potentiometer L1 see text U1 7805 N.B. This may be changed for different output voltages e.g. 7812 for higher output voltage ZD1 15V zener @ 1.3W The specific inductance of the ferrite (core)is important. A core should be chosen to work within the specific frequency as stated by the manufacturer. L1 is a powder core and has 32 turns of 0.75mm wire. The transformer has a 240V primary and has a secondary rated 24V at 2A. The bridge rectifier contains 4 diodes, their current rating needs to be high with respect to the transformers output current; if not the current may damage the diodes. C1 is the mainfiltering capacitor, the suppl...