Simple Mini Power Inverter

Even robot systems occasionally need a negative supply voltage for some purpose or other, and in this kind of application in particular there is a need for an effective circuit that does  not  make  greater demands  then  necessary in terms of current or space. If a low current 5 V supply is needed and only +5 V is available, a natural manufacturer to turn  to  is  Maxim,  and indeed in this case they do not let us down.The best known integrated  circuit made by this company is the MAX232, a level shifter for serial ports with an integrated charge pump that does not need an external inductor.

Simple Mini Power Inverter   image:

Along the same lines, although with a more stable output voltage and higher efficiency, is the MAX660. The device can ‘mirror’ any input voltage between 1.5 V and 5.5 V. With a 5 V input the output is typically –4.7 V with a load of 100 mA. Efficiency at 10 mA is around 96 % and at 100 mA is around 88 %. With an open-circuit output the IC draws a quiescent current of just 120 μA.There is little to say about the circuit itself.

Simple Mini Power Inverter Circuit diagram:

The 0 Ω resistor on pin 1 selects the operating frequency. With R1 fitted, the circuit operates at 80 kHz; without it, at 10 kHz. The combination of L1 and C5 slightly reduces ripple on the output voltage; the choice of inductor is not as critical as it would be if it formed part of the switching circuit.Gerber files for the printed circuit board (which uses some SMD components) are available for download from the Elektor website, ref. 070279-11.zip. R1, C1 and C4 are 0603 SMDs and C3 is an SMD tantalum electrolytic capacitor. Either the MAX-660CSA or the MAX660M can be used; both come in SO8 packages. L1 is a 10 μH SMD inductor rated at 300 mA.

Source: http://www.ecircuitslab.com/2011/11/even-robot-systems-occasionally-need.html 

Read more →

Simple 250W Inverter Circuit Diagram

This is a simple 250W Inverter Circuit Diagram. A 555 timer (IC1) generates a 120-Hz signal that is fed to a CD4013BE flip-flop (ICl-a), which divides the input frequency by two to generate a 60-Hz clocking frequency for the FET array (Ql through Q6). Transformer Tl is a 12-/24-V center-tapped 60-Hz transformer of suitable size. 

250W Inverter Circuit Diagram

Read more →

Inverter Overload Protector

An overload situation in an inverter may  permanently  damage  the  energy transistor array or burn off the transformer. Some of the home inverters bought in the market don't function an overload shutdown facility, whereas those incorporating this selection come with a ticket.the circuit presented here is an overload detector which shuts down the inverter  in  an  overload  situation.  

Circuit diagram:

Inverter Overload Protector With Delayed Auto Rest Circuit Diagram

 

It  hasthe following fascinating features:

• It shuts down the inverter and additionally provides  audio-visual  indication  of  the overload condition.
• after  shutdown,  it  robotically restarts  the  inverter  with  a  delay  of  6 2ds. accordingly, it keeps the consumer from the inconvenience  caused  due  to  manually resetting the device or operating round in darkness to reset the gadget at night.
• It  permanently  shuts  down  the inverter  and  proceeds  to  give  audio warning,  in  case  there  are  more  than three  successive  overloads.  Under  this situation, the device has to be manually reset.(Successive overload situation point outs that the inverter  output  is  short-circuited or a heavy current is being drawn by using the connected load.)

Inverter Overload Protector With Delayed Auto Rest

The circuit uses an ammeter  (0-30a)  as  a  transducer  to  detect  overload situation.  Such  an  am-meter  is  generally  present in  almost  all  inverters.  this  ammeter  is attached between the bad provide of the battery and the inverter, as shown in Fig. 2. the voltage developed throughout this ammeter, due to the glide of current, could be very small. It is amplified by means of IC2, which is wired as a differential amplifier having a gain  of 100. IC3 (NE555) is linked as a Schmitt ‘trigger’, whose output goes low when the voltage at its pin 2 exceeds 3.3V. IC4 (again an NE555 timer) is configured as  a  monostable  multivibrator  with  a pulsewidth of 6 seconds. IC5 (CD4017) is a CMOS counter which depends the three overload  stipulations,  after  which  the  sys-tem has to be reset manually, through urgent push-to-on change S1. the  circuit  can  be  powered  from  the inverter battery. In standby situation, it devours 8-10 ma of present and round 70 mA with relay (RL1), buzzer (PZ1), and LED1 energised. 

Please note the following factors carefully:

• Points A and B on the enter of IC2 should be connected to the corresponding points (A and B respectively) throughout the ammeter.
• Points C and D on the relay terminals  have  to  be  related  in  series  with the  already  existing  ‘on’/‘off’  switch  leads of inverter as proven in Fig. 1. which method that some of the two leads terminated on the present  swap  has  to  be  minimize  and  the  cut ends must be connected to the pole and N/O contacts respectively of relay RL1.
• The  ammeter  must  be  related in sequence with the bad terminal of the battery and inverter, as shown in Fig. 2.Move the wiper of preset VR1 to the extreme position which is grounded. Switch ‘on’ the inverter. For a three00W inverter, connect about 250-260W of load. Now alter VR1 slowly, unless the inverter simply go again and forths or shuts down.  repeat the step if vital. Use good-quality preset with dust cover (e.g. multiturn trimpot) for reliable operation.the circuit can also be simply and success-fully installed with minimum changes to the existing inverter. the entire parts used are low-cost and easily avail-able. the entire circuit is often assembled on a general-purpose PCB. The value of the entire circuit including relay, buzzer, and PCB does not exceed Rs one hundred.

Author : Siddharth Singh - Copyright : EFY Mag

Read more →

500W Low Cost 12V to 220V Inverter

Note :This Circuit is using high voltage that is lethal. Please take appropriate precautions

Using this circuit you can convert the 12V dc in to the 220V Ac. In this circuit 4047 is use to generate the square wave of 50hz and amplify the current and then amplify the voltage by using the step transformer. How to calculate transformer rating

The basic formula is P=VI and between input output of the transformer we have Power input = Power output
For example if we want a 220W output at 220V then we need 1A at the output. Then at the input we must have at least 18.3V at 12V because: 12V*18.3 = 220v*1
So you have to wind the step up transformer 12v to 220v but input winding must be capable to bear 20A.

Source :  http://www.ecircuitslab.com/2011/08/500w-low-cost-12v-to-220v-inverter.html

Read more →