This is a basic unregulated Dual DC 6V Power Supply circuit. The output includes +6VDC, Ground, and -6VDC terminal. In the circuit below we use easily a little electronics components and so cheap.
But it is suitable for the small circuit. Because it can deliver current less than 50mA only. If we use more than this current. It will make the high ripple or high noise.
Working of Simple Dual 6V Power Supply circuit
In the circuit above. First of all, the 110V/220V-ACV flow to the primary transformer T1. It is step down transformer. To change 220VAC to about 6.3VAC at secondary.
Next, both diode – D1, D2 are the half wave rectifier. It converts AC into pulsating DC. The D1 for positive voltage and the D2 for the negative voltage.
Then, both capacitors C1, C2 are used for smooth a fluctuating current into the stable voltage at output about +8.4VDC and -8.4VDC (when low current load.)
In addition. We can reduce the output ripple by using large values for C1 and C2.
We put both resistors R1, R2 to reduce the current so it also reduces ripple.
Choosing the parts
The trasformer-T1 is 220V Primary, CT 6.3V at 100mA Secondary transformer.
We use Capacitors C1, C2 of 100uF 25V. Because the Capacitors volage must have a DC working voltage (WVDC) of at least 2 x 8.4V = 16.8 volts. But we buy 25V because the cost is same as 16V.
Each diode should have 1 PIV, Peak Inverse voltage, a rating that is at least twice the peak voltage from the transformer, 2 x 8.9 = 18V. The 1N4002 has a PIV of 100V.
Many people know that we use half rectifier which it has the high ripple problems. But we require only low current and low voltage. Therefore, it is the profer way for us.
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