Introduction: High Voltage Power Supply for Kirlian Photography
This Instructable is a companion to my two other Instructables on Kirlian Photography.
To create Kirlian photographs, like the Kirlian photograph of the U.S. quarter shown, you need a high voltage (HV) power supply. You want a power supply that can supply a steady continuous output rather than one that outputs pulses. A reasonable high voltage power supply for Kirlian ought to be about to supply 3000 to 10,000 (or more) volts. However, the output current supplied by these power supplies I feel ought to be kept quite low. I point this out because; I have seen experimenters using what I consider unsafe high voltage high current power supplies.
What makes a high voltage power supply safe? Keep in mind that “Safe” is a relative term; all high voltage power supplies are potentially dangerous and will give a shock if used incorrectly. What I personally consider a safe power supply is one whose output current is 1 milliampere (1 mA.) or less. I consider this low current to be non-lethal. And yes if you’re interested I have shock myself many times when creating Kirlian photographs with my 1 mA. HV power supply, while not pleasant, it’s obviously non lethal. Voltage doesn’t kill current does.
The trade off in using a low current HV power supply is the size of the object you can expect to use to create a Kirlian photograph. There is no hard and fast rule as to the size you can photograph with a 1 mA HV supply, but from my experience you can expect to photograph an object with a 3” x 3” surface area with little problem. Keep in mind that the object’s conductivity and topology factors heavily in the surface area one can expect to photograph.
Step 1: Unsafe Power Supplies
Before I move onto suitable power supplies for Kirlian photography I want to show you an example of an unsafe high voltage power supply. Neon Sign transformers are not safe, because they are high voltage high current. High current in these transformers varies between 20 to 30 milliamperes. I consider these transformers lethal. Do Not Use!
Other high voltage circuits not to use are circuits/devices made for stun guns, tesla coils, or any high voltage circuits/device that output more current than 1 mA.
Step 2: Important Safety Warning
This is a high voltage power supply that is intended for use by adults. Children should not build or operate this circuit. This circuit is available as a kit, and the kit is not intended for children!
Assembly of this circuit or kit requires high-temperature soldering and the use of sharp edged components and cutting tools. Some included components may become hot, leak, or explode if used improperly. The author and Images SI Inc. recommend that you wear safety glasses when building or working with any electronic equipment.
High voltage discharges and shocks can cause injury and/or death. Additionally high voltage electricity as generated by this assembled kit can cause damage to property. The author and Images SI Inc. disclaim any liability for damage or injury caused by the use or misuse of the High Voltage Power Supply circuit or Kit. By building this circuit or kit, you agree not to hold the author or Images SI Inc. liable for any injury or damage related to the use, misuse or to the performance of this product. This product is not designed for, and should not be used in, applications where the malfunction of the product could cause injury or damage.
Step 3: Before You Build
The first question is to build the circuit from scratch or buy the kit. To simplify construction I am showing the kit construction from my company Images SI Inc. But the circuit may be build on a prototyping pc board as well. The schematic and parts list are the same whether you use the kit or point to point wiring on a breadboard. The kit just makes it easier.
Aside from the high voltage power supply kit shown here, there are other companies, such as Information Unlimited that also sell high voltage power supplies and kits.
Power Supply Features:
This high voltage power supply features variable frequency control. It also has a High-Low frequency range switch. In addition, this circuit can be either battery powered 12 VDC, or powered from a wall transformer, 9-12 V with either an AC or DC output. Powering the unit from batteries provides the advantage of portability for fieldwork.
Step 4: How the Circuit Works
The circuit schematic for the high voltage power supply is shown in the following figure. This is a simple device that is based on the 555 timer. The 555 Timer is set up as an astable oscillator. The output signal from the 555 Timer is fed to the base of Q3, a 3055 transistor. The signal from the collector of Q3 is fed to the base of a high voltage transistor Q1 that turns the transistor on and off, controlling the current flowing through the induction coil T1.
The frequency of the 555 timer is controlled by the potentiometer and hi-low switch that adjust the timing capacitor. The potentiometer used in this circuit is a double-ganged potentiometer. Which means that it is two potentiometers that share a common shaft. A close up of the potentiometer is shown in Figure 5. The center terminal of the potentiometer is called the wiper. The two wipers of the potentiometers are soldered together and connected to pin 7 of the 555 Timer. All the current to energize the HV ignition coil passes through transistor Q1. To prevent Q1 from overheating, a large heat sink is attached.
Step 5: T1 High Voltage Coil
The transformer T1 is a high voltage autotransformer. The T1 ignition coil transformer is a three terminal device. Figure 2 shows where we connect power from our circuit to the coil. The coil has a plastic protuberance that is the high voltage output of the transformer. A well-insulated (HV) wire is molded to this protuberance. The leads on the PC board labeled HV coil+ and – are used to connect T1 to pcb.
Step 6: Construction of High Voltage Power Supply
The components are mounted on the top side of the PC board. The top side of the board has white silk screen component drawings. The components are soldered on the opposite side of the pc board. After soldering the component to the board, any excess wire is clipped off.
Begin construction by mounting and soldering the 8-pin socket. Insert the IC socket, making sure to orient the notch on the socket to the drawing on the PCB and solder to the PC board.
Next mount and solder Q2, the 7805 voltage regulator and Q3, the 3055. Mount and solder R1, the 15K (color bands brown, green, orange) resistor and R2, the 4.7K resistor (color bands yellow, violet and red). R3, the 100 ohm resistor (color bands brown, black, brown), R4, the 330 ohm 1/2 watt resistor (color bands orange, orange, brown), and R5, the 33 ohm resistor (color bands orange, orange, black) should now be mounted and soldered. Next mount and solder the bridge rectifier D1, making sure to orientated the + pin of the rectifier to the silk screen. Now, mount and solder capacitors C2 and C3, 330uF capacitors. Next mount and solder D2, the 1N5401 diode and C5, .01 uF capacitor.
Wire the double ganged potentiometer as shown in Figure 5. Next, solder the opposite ends of the wires to the printed circuit board, in the box labeled “POT”. The center wire of the potentiometer is soldered into the center pad on the labeled box. The two end wires are soldered into the pads on either side of the center position.
Mount the Q1 transistor to the black aluminum heat sink. Next, mount the heat sink and transistor to the Q1 position on the PC board. The heat sink has two feet that fit into the holes on the PC board. Solder the heat sink feet in the holes to make a mechanically strong bond.
Attach 6 inch wires to both switches SW1 and SW2. Solder opposite ends of the wire into the pads marked SW1 and SW2 on the pc board respectively. Switch SW1 controls power to the circuit. Switch SW2 is the frequency high-low frequency control. Mount and solder capacitors C1 (.047uF), C4 (.1uF) to the PC board. Solder two 10” lengths of wire to the HV coil pads on the PC board. Attach the crimp terminals to the opposite ends on these wires. The quick disconnect terminal attaches to the (+) wire; the ring terminal to the (-). Attach these terminals to the HV coil as shown in Figure 6. Making sure to place the (+) lead to the (+) terminal on the HV coil. See Figure 2.
Attach power leads to either the AC input or DC input pads on the PC board.
Next install the integrated circuit. When installing integrated circuit (IC) chips, begin by first identifying the top of the chip. The top of the chip has a marker, many times it is a half circle cutout. Sometimes it is a small mark identifying pin 1 on the IC. In both cases the marks show us the top of the IC chip. Orientate the top of IC chips with the white silk screen drawings of the components on the top of the pc board (usually a half circle cutout) or on the parts placement drawings and install the IC into their socket. The leads on the PC board labeled M+ and M– are not used.
Step 7: Testing and Finishing Construction
To test the circuit, take the open end of the HV wire and place it about ¼” away from the (-) terminal on the ignition coil. Apply power to the circuit. An electrical discharge should jump between the HV wire and the negative terminal of the ignition coil. Adjust the potentiometer (frequency control) to obtain the largest spark across the discharge.
If you do not get a continuous HV spark, you have a board error. Go back to your pc board and start checking your components and soldering.
The working circuit should be mounted inside a plastic enclosure. Coat any exposed wires with a plastic spray to provide insulation (No-Arc spray is available at your local Radio-Shack store. Corona dope is another insulating material. In a pinch you can use clear nail polish. Since nail polish is flammable, allow the nail polish to completely dry before using the circuit.)
Step 8: Enclosure
You have completed the HV circuit and tested it. You can use the circuit as is, but it is a better idea to enclose the circuit inside a plastic case. I recommend a plastic case, to help eliminate shorts and shocks.
The size of the case I used is 6”x 6” x 3.25” deep. Any size case large enough to hold the circuit may be used. I created a decal for the top of the enclosure that you can download and print for free from the Imagesco website.
Step 9: Internal View of Enclosure
I improved the standard circuit by adding an On-Off power switch that controls power to the unit. I upgraded the Discharge switch from a standard on-off toggle switch and made it a Normally Open (OFF) momentary contact switch. To activate the HV power supply (turn on) both the On-Off power switch must be On AND the Discharge switch must be pressed.
Using a momentary contact switch makes it easier to time exposures.
The photograph above shows how I placed the circuit board, HV transformer and high voltage socket inside the plastic enclosure. Notice that the 12V power transformer is not mounted inside the enclosure. I decided to use a 12 volt wall transformer. The transformer has a 2.5mm power plug. So I mounted a 2.5mm power socket inside the enclosure to connect the external power to.
Handling high voltage is always a concern. So to make connecting to the high voltage power supply safer I decided to use connectors specifically manufactured for high voltage see next step.
Step 10: High Voltage Connectors
These are the voltage connectors I used, a socket and a plug.
I connected the high voltage output from the HV power supply to a HV socket I mounted on the wall of the plastic enclosure. Notice I used non-conductive plastic screws and nuts to mount the HV socket. The reason was to not give the HV power a conductive object to possible spark and jump to. See picture below. After I attached the HV wire to the socket, I coated the metal screw and nut of the HV socket with hot glue as an added measure of insulation and to prevent the nut from getting loose.
To connect anything to the high voltage power suppy I used the high voltage plug. So the high voltage wire from the Transparent Discharge Plate (TDP) is connected to a high voltage plug, which in turn is plugged into the socket.
In another Instructable I show how to build a Transparent Discharge Plate for Kirlian Photography, and how to take Kirlian photographs using the TDP and this High Voltage Power Supply.
Step 11: Parts List
HVPS-01 Parts List
Heatsink for Q1
C1 .047 uF, 100V capacitor
C2,C3 330 uF, 16V capacitors
C4 .1 uF, 100V capacitor
C5 .01 uF, 100V capacitor
Q1 HV Transistor IRF830 or Equivalent
Q2 7805 Voltage Regulator
Q3 3055 NPN Transistor T0220
U2 LM555 Timer
8 pin socket
T1 HV transformer (HVT-09)
R1 15K 1/4 watt resistor
R2 4.7 K 1/4 watt resistor
R3 100 ohm 1/4 watt resistor
R4 330 ohm 1/2 watt resistor
R5 33 ohm 1/4 watt resistor
R6 2.2 Mega ohm 1/4 watt resistor
D1 Bridge rectifier (BR-4A-100)
D2 1N5401 diode
SW1,SW2 SPST toggle switches(SW18)
POT double ganged 10K potentiometer
(1) Screw 540x3/8 PH Z
(1) Nut 540x5/16 SS
(1) Ring Terminal (blue)-Terminal-34161
(1) 1/4" Quick Disconnect Terminal (red)
(1) Screw 1024x5/8-PH
(1) Nut 1024x3/8Z
Book on Digital Kirlian Photography from Amazon