I am yet another software developer trying to step into the world of electronics... (so sorry for the basic questions...)
I am trying to understand how a capacitor works, but obviously I am missing a crucial part from all the helpful websites like sparkfun and adafruit.
I failed to solve an issue I currently have in a pretty basic project that reads a temperature from a thermocouple and displays the value on an LCD. An electrical engineer at work pointed me in the direction of adding a capacitor to filter the noise I introduce when I touch the thermocouple. Long story short; the capacitor doesn't seem to charge, no matter how I add the capacitor to the circuit, almost no voltage comes out; ever.
So I thought to be smart, and make a new circuit of:
- a battery supply (9.6V)
- an LED
- a capacitor "104"
The circuit is simple, all components are in series, so I expected that my LED would light up, and when I disconnect the battery, the LED would fade out. But again... nothing happens. The LED never lights up, and my multi meter measures 0.8V after the capacitor. But also, when I hold the multimeter probes to the leg of the capacitor, the measured voltage drops from 0.8V to close to zero in no time.
Please forgive me if this drawing is wrong (and please do tell me what is wrong so that I can learn from it):
- Why doesn't the capacitor charge up to the voltage of 9V (but seem to stop charging at 0.8V?)?
- Why does it discharge when I measure the voltage with a multi meter?
PS: there is no resistor between in the circuit limiting the current, and the batteries are 8x 1.2V rechargeables = 9.6V