+/-9V Dual Power Supply from 3V

No need to provide multiple power source to a circuit when you can boost and invert from single power supply source, in this article simple +/-9V Dual Power Supply from 3V supply prototype is designed by using Timer IC 555 as a main element.




Output square pulse from the timer IC 555 is converted into positive and negative by using rectifier diode setup. This circuit utilize 3V power source and provide Positive 9 volt and Negative 9 volt as output.

Circuit Diagram

Components Required

  1. Timer IC 555
  2. Diode 1N4007 = 4
  3. Resistor 1KΩ, 10KΩ each one
  4. Capacitors 10µF = 2, 4.7µF =2
  5. Capacitor 470pF, 0.01µF each one

Construction & Operation

In this boost converter circuit Timer IC 555 is configured in Astable multivibrator mode, hence it oscillates constant continuous square output pulse. Oscillating frequency is depends on the timing Resistor and timing Capacitors.

Here, RA = R1, RB = R2 and C = C1.

For positive and negative conversion two types of Rectification setup is made by diodes and capacitor. Output pulse from the timer IC is directly applied to the Rectification setup. We know square pulse has the Positive and Negative side and by rectification we can remove unwanted part. Here first rectification circuit removes negative part and provides +9V, Second rectification circuit removes positive part and provides -9V output. C3 and C5 Capacitors are used for charging and discharging the voltage by square pulse.

Timer IC 555

Dual in line package 8 pin timer IC is used in this prototype circuit. The Timer IC 555 is highly stable device for generating accurate time delays or oscillation. It can operate by using 3 volt to 12 volt. If the timer IC 555 configured in astable mode that is pins 2 and 6 connected, it will trigger itself and free run as a multivibrator. Ther external capacitor C1 charges through R1 + R2 and discharge through R2 and hence the duty cycle set by the ratio of these two timing resistors. In astable multivibrator mode of operation, the capacitor C1 charges and discharges between 1/3 Vcc and 2/3 Vcc.




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