What is the purpose of the capacitor connected to the ground tab of the voltage regulator? Is it still available from GM? Or shops such as NAPA?
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Re: C2 Voltage Regulator Capacitor
A capacitor functions in much the same way as a condom. It holds the charge but passes the effect. Most of the vendors such as LICS and Paragon carry them. I doubt if your local auto supply would have anything close.
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Re: C2 Voltage Regulator Capacitor
I suspected as much. For some reason I thought the capacitor at the coil under the ignition shielding was the only one needed.Comment
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Explanation is 'close' but highly simplified!
Capacitors are energy storage components. They block the flow of DC current, storing the electrical current in the form of electrical charge. Hence, the archane term of 'condensor' serves as a substitute for the modern term capacitor--electric current flow was blocked or 'condensed'...
Now, when you apply time domain calculus to the basic equation governing a capacitor (q = CV) where q = electrical charge measured in coloumbs, C = the capacitive constant associated with a given unit, it's storage capacity, and V = the voltage applied across the device, you get:
dq/dt = d[CV]/dt
dq/dt is an entity in electrical engineering, the change in charge per unit time, or current flow measured in amps. Since the storage capacity of the unit is fixed there is no time change associated with C and the equation reduces to:
I = C [dV/dt]
This says the current flowing through a capacitor is a variable based on the change in volage over time. DC voltage is constant, so there's no current flow through a capacitor. But, AC voltages (alternating current) WILL flow through a capacitor!
The voltage regulator is a switching component, turning the generator or alternator ON/OFF as needed to recharge the battery. As such, each time the V-Reg switches, it creates both DC as well as unintended AC (the radio frequency interference components). By hanging a capacitor across the output of the voltage regulator to ground, AC components flow through it and dissipate (hush up the noise at its source) but DC voltage is blocked and flows on to the generator/alternator to do its 'thing' (turn the gen/alt ON or OFF as needed).
Now, you know the rest of the story! That's why you see capacitors strategically placed here/there on radio equipped cars. They're positioned adjacent to the source of noise components that could interfere with radio signal reception and 'kill' them by gating them to ground at the point of their origin.
The capacitors do NOT muffle or bundle and store the noise components as was suggested. They simply give the noise a convenient alternate path to ground allowing them to 'die'...Comment
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Re: Explanation is 'close' but highly simplified!
Jack,
Thank you for that very thorough explanation!Comment
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and the rating is (point) 5 microfarad, not 5
as stated in the '65 TM & JG, 5th ed. Notice the decimal. These are abundant in junkyards, which is where I found this volt reg (July 1967 = 7F). Sprayed with black enamel, which had the effect of preserving the cad-plated parts.
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