Capacitors are energy storage devices. Once charged, they store energy for eventual release. Because capacitors are frequency dependent, they block direct current (DC) and pass alternating current (AC). Capacitors have a direct relationship with current, where, if you increase the capacitance of a circuit, you increase the AC current. On the other hand, diodes are used to convert AC current into DC current. When this happens, DC current increases.
Increasing Amperage with Capacitors
Connect a capacitor in series with a resistor in your circuit, similar to an RC circuit. For example, an RC circuit consists of a voltage supply, "Vs," connected in series with a resistor, "R," and a capacitor, "C," connected in series with the resistor.
Calculate the current using the formula I (t) = Vs/R * e^-t/RC where t stands for the elapsed time since the power supply, Vs, was turned on and I(t) means current that changes with the elapsed time. For example, if Vs is 120 volts, R is 300 ohms, C is 5 nanofarads and t = 3 microseconds:
C = 5 nanofarads or 0.000000005 farads or 5 x 10^-9
RC = (300)(5 x 10^-9) = 0.0000015 or 1.5 microseconds. Convert to microseconds to get RC in the same units as t.
I (t) = 120/300 * e^-3/1.5= 0.4 (e^-2) = (0.4)(0.8) = 0.32 amps.
Increase the current level by increasing the value of the capacitor. For example, increase the value of the capacitor from 5 nanofarads to 5 microfarads:
C = 5 microfarads = 0.000015 farads = 5 x 10^-6.
RC = (300)(5 x 10^-6) = 0.0015 or 1,500 microseconds.
I (t) = 120/300 * e^-3/1500 = 0.4 (e^-0.002) = (0.4)(0.998) = 0.3992.
The current increases as you increase the value of the capacitor.
Increasing Amperage with Diodes
Decide where in the circuit you wish to convert AC current to DC current. Generally, you do it at the source of the current.
Connect a diode in series with the current source. You do this by connecting the back or the "anode" of the diode to the source.
Power up the AC current source and you will see DC current on the output end of the diode.