This would seem to call for a solvent a little stronger than the lab standard, isopropyl alcohol (IPA). There comes a time when contacts need cleaning, though, and that job mainly consists of removing oxidation. Snubber capacitors can be used to remedy this. If the wetting current is too low, contacts that appear to be physically connected might actually still be open electrically. Wetting current is the minimum current needed to “punch through” the resistance of the oxide layer on contacts. Wetting current is one way of dealing with oxidation. But either way, the heat produced by the arc oxidizes the contacts and can produce debris that interferes with conductivity.Ī certain amount of contact oxidation is unavoidable, and a properly engineered circuit will take it into account. In general, direct current is harder on contacts than alternating current, because AC arcs tend to self-extinguish during zero-crossing. Arcing across contacts can cause corrosion and oxidation too. The copper and zinc oxides are nowhere near as conductive as either base metal, so electrical contacts made of brass can have problems if there’s too much oxidation on them.Įxposure to the atmosphere isn’t the only source of trouble for contacts. Other times, metal oxides cause problems. Sometimes this is handy, as when an aluminum screen door forms a layer of aluminum oxide that makes it essentially impervious to further corrosion. Pure metals rapidly combine with oxygen to form metal oxides, which usually have different properties than the base metal. Oxygen in the atmosphere is the culprit, and metals are the victims. It may not seem like it, but we live at the bottom of an ocean of corrosive gas. Oxidation is the Enemy Badly oxidized game cartridge connectors. With that in mind, I thought I’d look at contact cleaners that are in use today, what’s really going on when you clean contacts, and why contacts even need cleaning in the first place. All I know is that I’ve never found its equal for cleaning electronics gear. I never knew for sure if that stuff was Freon, but it was the mid-80s, shortly before CFCs were banned, so it might have been. He gave me some for my shop in a little jar.
He had a 5-gallon pail of cleaning solution under his bench that he told me was Freon, which he swore by for head cleaning and general contact cleaning. I was working for a video production studio at the time, so there was a fair amount in common about our jobs. One of the regular chores we faced was cleaning the heads on tape machines. I visited him at work once, and despite the fact that he wouldn’t let me climb the 1,200′ antenna tower, I had a great time.
HOME DEPOT CONTACTS CLEANER TV
I had a friend who was an engineer for a small TV station.
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