The slides explain how a voltage inverter can be made using 555 timer in astable mode. It contains a clear description of the working of the 555 timer and hence the voltage inverter.

1. Voltage Supply Inverter Using IC 555
SUMAN HOSMANE
SURAJ DONTHI

2. Intro
Whats a power sopply???

3. A power supply is used to convert an
input electrical energy to the required
electrical specifications of a load
In our mini project we have used a
variable power supply….

4. Classification
AC Power Supply
DC Power Supply

5. AC Power Supply

6. DC Power Supply

7. Common Sources
Batteries, Thermocouples, solar cells,
dynamo…..

8. Voltage Invertors
•Extensively used in the analog domain
•Most circuits incorporate voltage invertors
•Generally as dual power supply

9. Few Commonly used Inverters
◊ICL 7660
◊Op-amp sign changer/inverter
◊IC555 timer in astable multivibrator mode.

10. IC 555 Timer
Extensively used in pulse generation,
PWM, oscillators, time delays

11. Pin Layout

12. Internal Structure

13. Modes
Astable mode
Bistable mode
Monostable mode

14. The Astable Mode
DC to AC
Produces square waves at Vo
Produces square waves at Vc

15. Circuit Diagram

16. Time Calculation

17. Avoid low values of R1 so that o/p is
saturated
0V-2/3 Vcc in 1st cycle
1/3-2/3 Vcc in subsequent cycles

19. Astable Multi Vibrator as Voltage
Inverter

20. During +ve half cycle:
◦The diode eliminates the -ve DC
component
◦Fed to the –ve potential line to convert to –
ve
During –ve half cycle:
The –ve voltage is let out through the diode
D2 as it is.
Working

21. Overall O/P
Finally the th o/p is got across the 100uF
Capacitor at V0
The o/p is slightly smaller.

22. Calculation
The output frequency of the circuit
constructed is given by the
f = 1.449 / [(4.8+66)* 10^3 * 22 * 10^-6]
f = 1.449 / 1.5576
f = 0.93 Hz

23. Duty Cycle
T on = 0.693(Ra + Rb) C
= 0.693 (4.8 + 33) * 10^3 * 22 * 10^-6
= 0.57629s
T off = 0.693(Rb) C
= 0.693 (33 * 10^3) (22 * 10^ -6)
= 0.593s

24. Advantages
Used to run op amp which requires Vcc
and –Vcc for its working.
Circuits that require both negative and
positive voltages for their working can
incorporate such circuits.
Eg:

26. Reference
CicuitsToday