From simple LED light to embedded boards all need clean regulated
DC power supply. Here we give few schematic diagrams to build
power supply circuits from simple to complex types. If power
consumption is a critical factor go for switching only.
Here is one most popular, old, reliable and simple circuit for
fixed DC power supply. These are ideal for circuits with an
average current requirement of less than 1.00 amp.
5V/9V/12V fixed power supply
(Positive) at 1 Ampere current rating
Circuit Diagram (Schematic Diagram)-1
L1 = Step down transformer with i/p of 230 AC 50 Hz and output
of (XX ) - 0- (XX)) volts(rms).
XX = Required DC output voltage.
Here is the table for different voltages
| Output voltage (DC Volts) |
Transformer rating (rms Volts) |
| 5 |
230: 5-0-5 |
| 9 |
230:9-0-9 |
| 12 |
230:12-0-12 |
| 15 |
230:15-0-15 |
The current rating has to be more than 1 Amp.
D1, D2 = Diodes 1N4003
D3 = Diode 1N4003/ 1N4001 (optional)
C1 = 1000 Micro Farad aluminum electrolytic capacitor (For
loads less than 100mA you can sustitute with 220 microfards
capacitor), Voltage rating = 2.5 times of Output Voltage.
C2 = 10 Micro Farad aluminum electrolytic capacitor
IC1 = 7805 for + 5V DC output
=7809 for +9V DC
output
=7812 for +12V DC
output
=7815 for +15V DC
output
5V/9V/12V fixed power supply
(Negative) at 1 Ampere current rating
Circuit Diagram (Schematic Diagram)-2
L1 = Step down transformer with i/p of 230 AC
50 Hz and output of (XX ) - 0- (XX)) volts(rms).
XX = Required DC output voltages.
| Output voltage (DC Volts) |
Transformer rating (rms Volts) |
| 5 |
230: 5-0-5 |
| 9 |
230:9-0-9 |
| 12 |
230:12-0-12 |
| 15 |
230:15-0-15 |
The current rating has to be more than 1 Amp.
D1, D2 = Diodes 1N4003
D3 = Diode 1N4003/ 1N4001 (optional)
C1 = 1000 Micro Farad aluminum electrolytic capacitor(For
loads less than 100mA you can sustitute with 220 microfards
capacitor). Voltage rating = 2.5 times of Output Voltage.
C2 = 10 Micro Farad aluminum electrolytic capacitor
IC1 = 7905 for -5V DC output
=7909 for -9V DC
output
=7912 for -12V DC
output
=7915 for -15V DC
output
Datasheet link: 1N4003 - www.fairchildsemi.com/ds/1N/1N4007.pdf
78XX
- www.fairchildsemi.com/ds/LM%2FLM7805.pdf
(more circuits can be found in this datasheet)
79XX-
www.fairchildsemi.com/ds/LM%2FLM7905.pdf
Additional note: It's safer to put one heat sink to 78XXX
and 79XX IC for safeguarding the IC from overheating
In case you are using both the power supplies the ground connection
of both positive and negative power supplies can be shorted.
Effecient and
advanced DC power supply circuits - will be published soon.
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