Sparks ‘n Arcs
Experimenting with a Jacob’s Ladder
Published in issue 351, February 2006
Some people find electric arcs scary, while others find them especially fascinating. If you’re not afraid of a few kilovolts and observe due safety precautions, you can use the circuit described here for some interesting experiments. However, you must always remain alert and keep safety in mind, because the voltages and currents generated by the circuit can have nasty consequences.
If you search the Internet for things related to high voltage, you quickly encounter terms such as ‘Tesla coil’ and ‘Jacob’s Ladder’. In its original form as invented by Nikola Tesla, a Tesla coil is an air-coupled transformer that works entirely on the principle of resonance and can easily generate potentials of several hundred thousand volts or even a few million volts. At such voltages, electric arcs jump randomly to surrounding objects, and we do not regard that type of experimenting as something that can be responsibly suggested as an example.
Supply board
Resistors:
R1 = 12k
R2,R4 = 12
R3,R5 = 33
R6 = 47 5W
R7,R8 = 330 10W
R9 = 6k8
R10 = 470 5W
P1 = 25k preset
Capacitors:
C1 = 150pF
C2,C4 = 10µF 63V radial
C3,C5 = 100nF ceramic
C6 = 100µF 25V radial
C7 = 1nF 400V MKT
C8 = 4µF7 100V MKT, lead pitch 27.5mm
C9 = 100nF 100V MKT
C10,C11 = 1000µF 100V radial, max. diameter 18mm
C12-C15 = 47nF 250V MKT
Inductor:
L1 = 10µH
Semiconductors:
D1,D2 = BY448
D3 = zener diode 10V 1.3W
D4 = zener diode 15V 1.3W
D5 = LED, low-current
D6 = 1N4004
D7-D10 = BY329-1000
T1,T3 = BC337
T2,T4 = BC327
T5,T6 = IRF640 or IRFB260N
IC1 = 4047
IC2 = 78L09
Miscellaneous:
K1-K4 = 2-way PCB terminal block, lead pitch 5mm
K5,K6 = -way PCB terminal block, lead pitch 7.5mm
TR1 = 2 x core B64290-L82-X830 (N30, 50 x 20 mm)*, e.g.. Epcos (Schuricht cat. no.: 330603); 2 x 12 turns. 0.8mm ECW primary (approx. 2 times 1.5m); 2 x 75 turns. 0.5mm ECW secondary (approx. 2 times 8m) F1 = fuse 5A/T (slow) with PCB mount holder
F2 = fuse 1A/T (slow) with PCB mount holder
2 x heatsink type SK129 63,5 STS (Fischer/Dau Components) (63.5mm high, 4.5K/W)
Mains transformer, secondary 2 x 30V @ 225VA, e.g. Amplimo/Jaytee # 68017
PCB, ref. 050192-1 from The PCBShop
Cascade board
Capacitors:
C1-C20 = 5600pF 2000V, Panasonic (High Voltage Disk Capacitor (Y5P) ECK3D562KBP), Digi-Key # P9574-ND
Semiconductors:
D1-D20 = DSA 1-18D (1800 V/7 A) IXYS, Digi-Key # DSA1-18D-ND
Miscellaneous:
PCB, ref. 050192-2, from The PCBShop
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Click below to download a PDF copy of this article from Elektor magazine. Please note. In view of the complexity of international markets, Elektor cannot guarantee the availability of components for this project.
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