Checking that capacitors are discharged.

[Collaro]

I get the gist of this, but, forgive my ignorance, what is an "ultor dimple", and " 'dagging"?

---
Mike

[ms660]

Final anode connection.

Aquadag.

Lawrence.

[turretslug]

Sorry, yes, slipping into vernacular- thanks Lawrence!

Aquadag- an aqueous solution of fine graphite applied to e.g. A glass CRT bulb, where it dries to a conformal conductive coating and forming an inexpensive HV capacitor of perhaps a nF or so in conjunction with the inner aluminising,

Colin

[Craig Sawyers]

DAG stands for (for what it is worth) Deflocculated Acheson Graphite. A proprietary name for the base product. AquaDAG is the same stuff dispersed in water.

Crag

[Phil G4SPZ]

For 'normal' radio-type HT up to a few hundred volts, an Avo Model 7 on an appropriate voltage range makes an effective discharger, and even shows you what's happening!

[ColinTheAmpMan1]

Originally Posted by Craig Sawyers

DAG stands for (for what it is worth) Deflocculated Acheson Graphite.
Crag

Does that mean that you have changed your name to Commercially Rare Acheson Graphite?

There is also Oildag, which is suspended in oil rather than water.

Colag .

[turretslug]

Aha, I'd wondered what the "dag" bit stood for- though not enough to lose sleep or do a search....

I agree with Phil's point- a combined resistive and visual discharge makes good and safe sense. Resorting to screwdriver blades might be reassuringly macho but raises the discussed risk of dielectric absorbtion, not to mention all the other possible knock-ons of sudden high currents.

[Craig Sawyers]

Originally Posted by ColinTheAmpMan1

Does that mean that you have changed your name to Commercially Rare Acheson Graphite?

There is also Oildag, which is suspended in oil rather than water.

Colag .

Duur. Comes to a fine pass when I cannot type my own name correctly

Covfefe

[Herald1360]

For an idea of how dielectric absorption behaves electrically, think of a capacitor as the nominal value of capacitor in parallel with several smaller ones each in series with a high enough resistance to give a long time constant.

[Collaro]

Really nice way of putting it - thanks!

[Collaro]

Originally Posted by ms660

Final anode connection.

Aquadag.

Originally Posted by turretslug

Sorry, yes, slipping into vernacular- thanks Lawrence!

Aquadag- an aqueous solution of fine graphite applied to e.g. A glass CRT bulb, where it dries to a conformal conductive coating and forming an inexpensive HV capacitor of perhaps a nF or so in conjunction with the inner aluminising.

Originally Posted by Craig Sawyers

DAG stands for (for what it is worth) Deflocculated Acheson Graphite. A proprietary name for the base product. AquaDAG is the same stuff dispersed in water.

A veritable vertical learning curve.

Thanks guys!

[emeritus]

In the early days of electricity, they were fond of the "hydraulic analogy" for explaining electrical phenomena. One I read that explained dielectric absorbtion was to consider a capacitor as a section of wide pipe with a rubber membrane across it, in series with a narrow pipe (resistance) connected to a pump (voltage source) via a valve (switch) in a closed circuit. When water pressure (voltage) is applied to one side by opening the valve and running the pump, the membrane stretches proportionately to the pressure. If the pressure is released by turning off the pump and opening the valve, the tension in the rubber will push the water back until the membrane is unstressed. However, rubber takes a while to return to its original state, so the membrane will not immediately return to its original position. Thus if the valve is closed, after a while stress will build up in the membrane as the rubber tries to return to its original position, which will pressurise the water again, causing more water to flow when the valve is opened again. Depending on the recovery time of the membrane, several discharges can be obtained over time.

[Collaro]

All really good stuff here. Thanks for sharing and taking the time to present it so clearly and eloquently!

---
Mike