Introduction: 555 Voltage Doubler
Batteries are a great way to add portable power to your project/device but often you require higher voltages than a single (or multiple) batteries can provide, this usually means connecting many batteries together to get the required voltage (which could add unwanted weight).
This Instructable uses a common 555 timer IC (available pretty much everywhere) to double the voltage of the input DC source while only using minimal external components. This circuit is only practical for low current devises where the input voltage (for the voltage doubler) is between 4-20Vs.
(Shown in Picture ^^^^ ~6V from 4X1.5V batteries being increased to ~13V)
Step 1: Materials and Diagram
The circuit is pretty straight forward to build. You can either build it on a breadboard for a temporary power supply or solder it onto a PCB and use it with batteries for a compact, light weight and portable power source.
• C1 100nF ceramic capacitor
• C2 1nF ceramic capacitor
• C3/4 4.7uF electrolytic capacitors
• D1/2 1N4004 diodes
• R1 39Kohm resistor
• 555 timer IC
You will also need some hook up wire for the links
Follow the schematic above for wiring details or follow on for breadboard instructions
Step 2: Building the Circuit (on a Breadboard)
*Refer to image for Vin,Vout and GND*
*Refer to image for breadboard pin connections -solid line indicates connection between breadboard holes*
Step 3: The Ground
Start by connecting the two GND rails on either side together, this is where everything connected to GND will go to.
Step 4: The 555 Timer
Simply place The IC in the middle of the breadboard with the little notch (or dot) at the top of the IC (point it up)
*refer to diagram for pin location*
Step 5: The Components
It's time to add the components!
We'll add them in steps
1. Connect one pin of C1 (100nf Capacitor) to the right GND and the other to pin 5
2. Connect one pin of C2 (1nf Capacitor) to the left GND and the other to pin 2
3. Connect the Resistor (R1-39kohm) from pin 2-3
4. Connect the pin of D1 without the silver (might be white) band to Vin and the other pin (with the band) to a free spot on the breadboard
5. Connect the negative pin of C4 to pin 3 and the positive pin to a blank spot on the breadboard below the IC
6. Connect the non-banded pin of D2 to the positive pin of C4 and the banded pin to a blank spot on the breadboard
7. Connect the negative pin of C3 to the right GND and the positive pin to the banded pin of D2
*your board should look something like the picture above*
Step 6: The Links
Now we must add the links (Using hookup wire)
We will also do this in steps
1. Add a link between the banded pin of D1 (that's the one connected to Vin) and the non-banded pin of D2 (this will also connect D1 to the positive pin of C4) -note this is the yellow link
2. Add a link from IC pin 4 to pin 8
3. Add a link from IC pin 8 to the Vin rail
4. Add a link from IC pin 2 to pin 6
5. Add a link from IC pin 1 to left GND
6. Add a link from the banded pin of D2 (or the positive pin of C3) to Vout
And we're done!
Step 7: Final Testing
Connect a 4-20V power source (batteries work well) to Vin (positive terminal to Vin negative to GND)
Use a multimeter to measure the voltage at Vout (Vout is the positive output terminal and GND will be the negative)
If the Circuit is not working make sure check all connections and components
-Note this will only double for input voltages above about 4V (you will get some increase for lower voltages but not double)
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