Some circuit required dual power for better operation like power amplifier, audio amplifier or other power circuit . That circuits made for operating with dual supply input voltage.
Dual supply means- One terminal gives +ve. One terminal gives -ve and one is for ground .
Two terminals gives +ve and -ve supply accordingly and third is grounded,
For example If any circuit required 12v dual supply that means it need three input - 1 is +12v 2 is -12v and 3 is Ground.
Here i am giving some circuit of dual power supply with regulated and non-regulated output.
• Center taped transformer is best for dual power supply circuit. It Means primery (input)has 2 terminals and secondary (output) has 3 terminals.
Select the diode for rectifier as per ampere required. You can use readymade bridge rectifier IC which is available in market with different current rating.
This is the general 12 V DC Dual power supply circuit . The output is not regulated of this circuit
The following circuit diagram gives regulated dual power output , Regulator ic is used in these circuit.
• 79xx ic used to regulate the negative input voltage where as the 78xx ic used for positive input dc voltage regulate.
• The pin configuration of LM 78xx and LM79xx are not same so careful when connect.
• The minimum input voltage should be greater than 3 volt than required output , if you use regulator ic. But if not ic used in circuit then the same voltage transformer use as output required.