i am trying to make dc dc boost converter using:

- mc34063 datasheet
- 100uf 16v capacitor
- 220 uf 25v capacitor
- 680 pf capacitor
- 1n5819 diode
- 180 ohm 1/4 watt
- 1000 ohm 1/4 watt
- 0.33 ohm 1 watt
- axial inductor 100 uh



here is the diagram and circuit







according to this formula < 1.25(1+R1/R2) > i calculated the output should be 8v

BUT the result is 0 v!!

what is the wrong?!

 

Your schematic has no supply voltage. If it is only 3.7V without a load then the battery is almost dead. It is 4.2V when strong and fully charged.

 

after adding this resistor, i got 1.80v output, replaced the ic but still same 1.80v

 

ops.. i found there are two resistors touch each other, now it is working 8v output
thanks

 

Solderless breadboards almost always have parts and wires touching.