Simple Electroscope

Materials:

Glass Jar or Glass
Aluminum Foil
Index Card
Paperclip
Tape

Background:
An electroscope is an instrument for detecting the presence of static electricity. It consists of two thin metal leaves suspended from a metal hook. When the hook is brought near a source of static electricity, some of the electrons in the hook are pushed to the leaves (if the source is negative) or pulled up to the hook from the leaves (if the source is positive). Either way, the leaves are now charged the same way as each other and so they repel each other. The amount they open up is proportional to the charge of the source (if the sources are always held at the same distance from the hook).

Procedure:
Cut two strips of foil lcm by 4cm (1/3" by 1 1/2") Open out the paperclip to form the shape at right. Push the hook through the middle of the index card and tape so that it is at right angles to the card. Lay the two foil strips on top of one another and hang them on the hook by pushing the hook through them. Lay the card over the jar so that the strips hang inside (see picture below).

Bring various charged objects near the hook and observe what happens. Notice what happens to the strips when the sources are removed. Does anything different happen if the source actually touches the hook? If the strips do not fall back together, gently touch the hook with your finger.

Licron Crystal ESD-Safe Coating

Licron Crystal ESD-Safe Coating<< Back

1756

Description

Versatile, crystal clear urethane coating that adheres to metal, plastic, and most other surfaces. Ideal for converting standard bumpers, bins, tools, and surfaces to ESD­ safe, saving expensive replacement cost. The end result is compliant with ANSI/ESD­S20.20, which prevents static damage to sensitive electronic components.

Features & Benefits

• Rugged static dissipative coating
• Surface Resistivity of 10^6 To 10^9 ohms
• Non-ozone depleting
• Operating temperature range – up to 302°F (155°C)
• Humidity independent
• Superior adhesion to variety of surfaces: glass, plastic, etc.

Instructions

Licron Crystal can be sprayed using standard spray guns or paint systems (test compatibility on seals and other plastic or rubber components). A grounding wire can then be attached (i.e. by conductive adhesive) similar to an ESD floor. 

Packaging & Availability

Sku Number	Name	Size	Regions
1756-8S	Licron Crystal ESD-Safe Coating	8 oz	US / Asia, Europe, Canada
1756-G	Licron Crystal ESD-Safe Coating	1 gal	US / Asia, Canada

Additional Information

•  1756-English.pdf

Category: ESD Products
Brands: Licron Crystal
Applications: ESD Environment, Janitorial / Sanitation

FAQ

• Q. Aerosols:
  How do I properly dispose of an aerosol can after it is empty? 
  A. It may be different state-by-state, so contact your state environmental agency for regional specific regulations. For a general guideline, here is the process according to EPA hazardous waste regulations 40CFR. The can has to be brought to or approach atmospheric pressure to render the can empty. Puncturing is not required, only that it “approach atmospheric pressure”, i.e. empty the can contents until it’s no longer pressurized. This insures that as much contents as is reasonably possible are out of the can. It is then considered “RCRA-empty”. At that point it can be handled as any other waste metal container, generally as scrap metal under the recycling rules. Note that the can is still considered a solid waste at this point (not necessarily hazardous waste).

Graphite Store: Graphite Plus Aeroso

Graphite Plus Aerosol

Grade: ASB-GraphitePlus

Enlarge Image

Multi-purpose flammable(!) graphite aerosol coating. Electrically conductive - bleeds static. Especially useful in dusty, dirty conditions where greaseless, oil-free lubrication is required – will not pick up dust or grit. Air dries quickly – requires no baking. Effective release and anti-weld coating. Break-in lubrication. USES: Maintenance: Conveyor chains, chutes, fork lift masts, rail or elevator guides, expansion pegs, water meters, fire hydrant plugs, firearms, sliding mechanisms, etc. Metalworking: Casting surfaces, run-out tables, release coating for extrusion dies. Production: Precoating gaskets, packings, threads, bolts, cams, precision parts prior to assembly of component parts. Can be used on metal, wood and plastic. Ideal for lubricating hard-to-reach areas and parts. For more technical data please refer to the product data sheet.

Part number:		MSDS:	Availability:
AS001025		msds	Usually ships in 1 business day
Price:	Unit:	Quantity:	Note:
$12.62	12ozCan		Buy 12 or more, pay $10.78 and save 15% Buy 24 or more, pay $9.24 and save 27%

Graphite 33 Spray

Graphite 33 Spray
All products by Kontakt-Chemie

An extremely useful aid for the application of conductive coatings of any thickness to any material including glass and plastics. Ideal for screening casings of plastic material or wood and the repair of damaged screens of cathode ray tubes. Assists with the elimination of static charges in plastic casings and the lubrication of high voltage switchgear.


Supplied in ozone friendly 200ml aerosol

MG Chemicals Conductive Coating; EMI/RFI Shield, 12oz Areosol

MG Chemicals 841-340G
841-340G

Reduces or eliminates EMI/RFI interference for low to mid range frequencies. A general purpose shielding spray for use on plastic electronics enclosures. Consists of a tough, durable acrylic base pigmented with high quality nickel flakes.

 

View More MG Chemicals Chemicals
View larger image

 

Conductive Coating; EMI/RFI Shield; 19% Nickel; Adheres to Plastic; 12oz Areosol

Mfr. Part#: 841-340G
Allied Stock#: 661-0610

  

Documents
Datasheet
Catalog Page #2148
RoHS Compliant part
Hazardous Materials

Pricing (USD) & Availability
Standard Pricing $34.95 (Each)
Availability 139 can ship immediately.
Min. Order QTY: 1|Multiples of: 1
 

Application : For reducing EMI⁄RFI interference
Chemical Component : 1, 1, 1, 2-Tetrafluoroethane/2-Heptanone/2-Methylpropyl Ester Acetic Acid/2-Propanone/Ethyl Acetate/Ethanol/Nickel/Toluene
Dispensing Method : Aerosol
Primary Type : Coating
Specific Gravity : 1.85
Time, Setting : 10 min.
Type : Conductive
Weight : 12 Oz.

Banging Heads with ANTLR: Changing Token Text

I'm hewing at the ANTLR parser generator documentation and find a lot of things that need to be discovered by trial and error.

Here's a simple way to change the text of a token. This example is the common problem of converting escape characters in text strings.

tokens {
   BACKSLASH   = '\\';
   DOUBLEQUOTE = '"';
   }

ESCAPE:
   BACKSLASH (
      | 'n' { setText("\n");}
      | 'r' { setText("\r");}
      | 't' { setText("\t");}
      | DOUBLEQUOTE { setText("\"");}
      );

stringQuote:
   q=DOUBLEQUOTE { $q.setText("");};

string:
   s=stringLiteral ->^(STRING[$s.text]);

stringLiteral:
   stringQuote ( ESCAPE | ~( DOUBLEQUOTE | BACKSLASH))* stringQuote;

The salient point here is that setText() changes the text of the whole token as it is ultimately presented to a parser rule. Therefore ESCAPE must be a complete token - not a fragment or referenced by another token. That makes stringLiteral a parser rule and not a token; otherwise the entire text would be overwritten by a setText().

Also the stringQuote production eliminates the delimiting double quotes from the text of stringliteral. If stringQuote were a token my grammar would be ambiguous.

The string production tidies up the tree by condensing the glob of token children of stringLiteral.into one node. If stringLiteral were a token the token fragments that compose it would combine into one node, but having to make it a parser rule makes a node with every token a child. I said this was simple?