How to create dual power supply unit using single battery for your lab prupose? Dual voltage power supplies are required particularly for op amp experiments and some of the instrumentation amplifiers. Some low power audio pre amplifiers also uses dual voltage supply. Here is a simple dual power supply schematic capable of producing +9V, 0V and -9V (dual polarity and ground potential) from a single 9V battery. You can create your own dual power supplies with different ranges of +Vcc and –Vcc such as +5V, 0V and -5V or +12V, 0V and -12V. This article gives the working and constructional details of the circuit schematic using single battery source.
- Dual power supply for your lab (Using step down transformer & Bridge rectifier)
(Click on the image for enlarged view)
- NE555 timer IC
- Negative voltage regulator IC 7909
- Diode 1N4007
- Resistors (470Ω, 0.5W x 2)
- Capacitors (0.01µF; 220µF, 16V x 4)
- 9V battery
- Timer IC NE555 is configured as a free running astable multivibrator oscillator. It provides approximately 100 kHz frequency. We have already discussed about astable multivibrator.
- The frequency of the astable multivibrator depends on the values of capacitor and resistors associated with 555 timer circuit. Our astable frequency calculator will help you decide them.
- The oscillating voltage (square pulse) is made ripple free using 1N4007 diodes and regulated to -9V by negative voltage regulator LM7909.
- Use 5V battery if you need to create +5V, 0V and -5V dual power supply unit.
- The operating voltage of 555 timer IC is approximately between 3V to 16V, so by changing the battery supply you can implement required dual power supply varies from 3V to 16V other than +9V, 0V and -9V supply.
Now power supply is ready for use in your lab. Feel free to ask for any help regarding the schematic. All the best. Cheers!
Pin out of 555 timer and 7909 Negative voltage regulator