Symmetrical Power Supply with IC 78 and 79 series

 

Parts :

Parts	Description
C1	100nF 250V Polyester Capacitor
C2, C3	1000uF 25V Electrolytic Capacitor
C4, C5,	100uF 25V Electrolytic Capacitor
Sw1	SPST
Sw2	SPDT
PL	Male Mains Plug
T	220V or 120V primary, 18V Center-tapped Secondary 500mA Mains transformer
F	100mA Fuse
DB	Bridge Diode 1A
IC1	7812 (see Notes)
IC2	7912 (see Notes)
MISC	Heatsink for IC

Regulated Power Supply with IC 78 and 79 series

Parts :

Parts	Description
C1	100nF 250V Polyester Capacitor
C2, C3	1000uF 25V Electrolytic Capacitor
C4, C5,	100uF 25V Electrolytic Capacitor
Sw1	SPST
Sw2	SPDT
PL	Male Mains Plug
T	220V or 120V primary, 18V Secondary 500mA Mains transformer
F	100mA Fuse
DB	Bridge Diode 1A
IC1	7812 (see Notes)
MISC	Heatsink for IC

 

For other Voltage Output, change IC1 with :

Voltage Output	IC1
3V	7803
5V	7805
9V	7809
15V	7815

etc

 

Symmetrical Power Supply

Parts :

Parts	Description
R1, R2	1 K Ohm ¼ Watt
C1	100nF 250V Polyester Capacitor
C2, C3	1000uF 25V Electrolytic Capacitor
C4, C5, C6, C7	100uF 16V Electrolytic Capacitor
Sw1	SPST
Sw2	SPDT
PL	Male Mains Plug
T	220V or 120V primary, 15V Center-tapped Secondary 500mA Mains transformer
F	250mA Fuse
DB	Bridge Diode 1A
D1, D2	BZY88 12V Zener Diode
Q	2N3055 NPN Transistor
MISC	Heatsink for Q

Regulated Power Supply with Zener Diode

 

Parts :

 

Parts	Description
R1	270 Ohm ¼ Watt
C1	100nF 250V Polyester Capacitor
C2	1000uF 25V Electrolytic Capacitor
Sw1	SPST
Sw2	SPDT
PL	Male Mains Plug
T	220V or 120V primary, 20V Center-tapped Secondary 3A Mains transformer (see Notes)
F	2A Fuse (see Notes)
D1, D2	IN5401 (see Notes)
D3	BZY88 12V Zener Diode (see Notes)
Q	2N3055 NPN Transistor (see Notes)
MISC	Heatsink for Q
Lp	12V 0.006A DC Lamp (see Notes)

Notes :

If we need lower power output, change :

Parts	Description
T	220V or 120V primary, 15V Center-tapped Secondary 1A Mains transformer
F	500mA Fuse
D1, D2	IN4001
Q	BD131 NPN Transistor
MISC	Heatsink for Q

 

Change D3 with another value, example : 3V, 6V, 7V, 9V, etc, if we need different Voltage Output.

We don’t have Center-tapped (CT) Transformer, use this circuit :

Unregulated Power Supply

Parts :

Parts	Description
C1	100nF 250V Polyester Capacitor
C2	1000uF 25V Electrolytic Capacitor
Sw1	SPST
Sw2	SPDT
PL	Male Mains Plug
T	220V or 120V primary, 12V Secondary 2A Mains transformer
F	1A Fuse
DB	Bridge Diode 2A
Lp	12V 0.006A DC Lamp

Parts :

 

Parts	Description
C1	100nF 250V Polyester Capacitor
C2	1000uF 25V Electrolytic Capacitor
Sw1	SPST
Sw2	SPDT
PL	Male Mains Plug
T	220V or 120V primary, 12V Center-tapped Secondary 2A Mains transformer
F	1A Fuse
D1, D2	IN5402
Lp	12V 0.006A DC Lamp

We can change Lamp with LED :