Loading... Please wait...


Our Newsletter

Toroids & HV Terminals

SHP4STEEl - Spherical Metallic Terminals
toroids, terminals We now can supply you with spherical metallic terminals for your projects. Not only do these pieces offer aethestic value they also provide an amount of capacitance for enhancing the output of Tesla coils and supply the surfaces necessary for reducing leakage in high voltage dc sources. All have 3/8" mounting holes (not threaded). View free PDF sheet for other available sizes up to 65 inches!
SPH4STEEL - 4" Steel Spheroid, Good Up To 140 kv ... $9.95
SPH2.5PSS - 2.5" Stainless Spheroid w/Brass plating, Good Up To 70 kv ... $9.95

Toroidal Terminals For HV Uses
Ready to use for Tesla coil and other high-voltage applications. If these will be used for high-voltage DC stacks or multipliers, they will need to be polished to a shiny mirror-like surface (you can do this yourself, or have it done for you).

Our laboratory has the tooling and now offers many sizes of toroidal terminals from 3" to 98". Have a look at our PDF sheet to see other available sizes from 3 to 98 inches!

These are spun aluminum of grade 1100-O (99% pure aluminum), with a welded seam on sizes above 12" that is smooth and cannot be seen. Aluminum wall thickness is approximately 1/16" (so the flat central area is about 1/8" thick, for example).

Excellent for Tesla coils requiring a capacitive terminal, and high voltage DC generators up to 1.5 million volts. (Note that high voltage DC generators require a highly-polished surface to prevent leakage losses, which is contrary to Tesla operation where you want air leakage to make the sparks. High voltage DC generators should also use seamless toroids as these are easier to finish to a smooth mirror-like surface.)

Toroidal terminals used for Tesla coils are for producing a capacitive load that lowers the impedance of the output, consequently giving a hotter and brighter spark. These pieces do not require smooth or shiny surface as do toroids used for high-voltage DC power supplies where smoothness is mandatory to prevent high-voltage Corona leakage.

Quantity discounts available. View free PDF sheet for other available sizes.

Free PDF sheet
available sizes up to 98"
TO8 - For coils up to 250kV, 8"x 2" with ¼" Center Hole (visible seam) ... $53.50
TO12 - For coils up to 500kV, 12" x 3" with ¼" Center Hole (visible seam) ... $89.50
TO18 - For coils up to 750kV, 18" x 4.5" with ¼" Center Hole (no seam) ... $312.50
    TO18N - The 18" toroid (with a visible seam) ... $200.00
TO20 - For coils up to 850kV, 20" x 5" with ¼" Center Hole (no seam) ... $421.95
TO24 - For coils up to 1Mev, 24" x 6" Welded with ½" Center Hole (no seam) ... $469.95
TO30 - For coils over 1Mev, 30" x 7" Welded with ½" Center Hole (no seam) ... $645.95
TO36 - For coils up to 1.5Mev, 36" x 6" Welded with 1/2" Ctr Hole (no seam) ... call or email
TO40 - For coils up to 2Mev, 40" x 10" Welded with 1/2" Ctr Hole (no seam) ... call or email
TO68 - For coils up to 2Mev, 68" x 18" Welded with 1/2" Ctr Hole (no seam) ... call or email


Please Note: Most of our toroids can be highly polished for Van de Graf and other high voltage DC applications Email us your specifications and amount required

Shipping: these are bulky items and shipping may exceed the website calculation for 18" and larger toroids. Please contact us, or we will let you know after your order has been placed if any additional shipping is required.

click to enlarge

OBLATE14 - Aluminum Oblate Terminal
Oblate Terminal We now can offer the high voltage researcher a 14-inch terminal that supports up to 500,000 volts. The 14" diameter (9" across the oblate) has a 3-3/4" hole for mounting onto an insulated column and can be used for the collector terminal of a Van de Graaff generator.

Temporarily unavailable, our apologies for that.