# Capacitor not charging up

Hello electronics experts,

I am basically a computer engineer but because of a robotics project i am in a need of designing small ups for few seconds backup ( Approximately 8-10 seconds ) but facing following problems -

1. Capacitor not charging up to 5 volt even if connected to power bank without using any resistor and without any load at the output.
2. Is a resistor is always needed if we wants to use a capacitor?
3. Is a load is always needed and then only capacitor will start conducting?

• 1) Find (by reading its spec) the current your supply (V1) can provide. (if V1 is a power bank, remember your capacitor can't negotiate over USB! ) 2) Use Ohm's Law to calculate R1 to provide that current from 5V. 3) Calculate the RC time constant ( R1 * C1) 4) Charge C1 for 5x that time constant. 5) measure voltage across C. – user_1818839 Apr 5 at 11:49
• How are you determining the Supercap is not charging up? – StarCat Apr 5 at 12:05
• @StarCat I am determining it with checking the voltage across the super capacitor terminals while the circuit is connected using multimeter – Rushikant Pawar Apr 5 at 14:03
• @Brian I didn’t get your point number 4. Can’t I keep the circuit as it is above and keep it on forever? I am going to use raspberry to output of above circuit. Does super capacitor just keeps sucking current and keep storing it even if it’s tummy is full to it’s capacity? – Rushikant Pawar Apr 5 at 14:08
• Is your supercapacitor rated for five volts? Many can't handle that much voltage, and would be destroyed by it. – Hearth Apr 5 at 14:57