Measurement is not the same as therapy
Biofeedback or bioresonance systems can include measurement or analysis of responses. A classic zapper, however, usually only generates and delivers a selected signal.
Today, the term "frequency device" is used for a very wide range of apparatuses. Some measure electrical responses and are used by therapists as biofeedback, others deliver micro- or low-voltage current through electrodes, a third group generates electromagnetic or pulsed magnetic fields, and a fourth uses a plasma tube. Therefore, two devices that both advertise "frequencies" do not necessarily operate in the same technical manner.
The most important question is therefore not just "how many frequencies does the device have?", but: how is the signal generated, within what range does it operate, what is its waveform and amplitude, how is it transmitted to the body, how well can it be programmed, and above all — for what purpose is the device designed.
Main families of frequency devices
Frequency is only one parameter
Voltage or current, waveform, duty cycle, offset, modulation, harmonics, time, and the mode of contact with the body are also important.
Electrodes, coils, and plasma are not the same
Contact current, magnetic field, and plasma emitter create completely different physical conditions. Therefore, the numbers on the display alone do not tell the whole story.
More programs do not necessarily mean a better device
Well-documented output, stable signal, sufficient programming options, safety, and a comprehensible protocol are often more important than the huge number of program names.
What exactly is a frequency therapy device?
One device has two electrodes and operates at 30 kHz. Another has thousands of programs in a computer database. A third uses a plasma tube, a fourth uses a pulsed magnetic field, and a fifth uses microcurrent and a smartphone app. All of these can fall under the same label of “frequency therapy,” but they involve very different technologies.
In the broadest sense, a frequency device is a device that generates a periodic electrical or electromagnetic signal. Frequency indicates how many times the signal repeats in one second and is expressed in hertz (Hz). However, frequency alone never fully describes the output.
Two devices set, for example, to 1,000 Hz can generate very different stimuli. One might produce a sinusoidal microcurrent, another a square wave with a DC offset, a third might modulate a high-frequency carrier wave, and a fourth might drive a magnetic coil with 1,000 pulses per second. Therefore, when comparing devices, it makes sense to consider the entire signal and output system, not just the frequency figures.
First, distinguish the purpose
Professional biofeedback or bioresonance systems, home-use contact generators, wellness microcurrent devices, plasma Rife systems, and regulated medical stimulators do not belong to the same category. Their intended uses, regulatory status, output power, method of use, and evidence base can vary significantly.
Bioresonance and Biofeedback Systems in Medical Practices
Larger systems are often used in therapeutic practices; in addition to pre-set programs, these systems also include various forms of measurement, program selection, or biofeedback. With these systems, it is important to distinguish between biofeedback or bioenergetic testing and conventional medical diagnostics involving laboratory tests, imaging, and other validated diagnostic procedures.
BICOM: One of the Most Established Commercial Bioresonance Systems
The German BICOM is one of the most recognizable systems in bioresonance practice. The first BICOM was introduced in 1987. According to the manufacturer’s technical specifications, today’s BICOM Optima has a frequency range from 1 Hz to 250 kHz; the Optima and Optima Mobile versions are marketed in Europe as Class IIa medical devices for specific purposes.
It is interesting to note that the manufacturer itself clearly distinguishes its position within complementary medicine: it describes BICOM as a bioresonance method, yet at the same time states on its website that the method is not generally recognized in conventional medicine.
Quantum SCIO or Biosyn QS
Another well-known system is the Quantum SCIO, which is linked to computer-guided electrophysiological biofeedback. In recent years, SCIO International has renamed its product line Biosyn QS. The manufacturer describes the system as an advanced biofeedback tool for professionals in the fields of integrative wellness and complementary approaches.
Older presentations of the system often mention the very rapid analysis of several thousand data or program entries. Such figures should be understood as referring to the scope of the software database and the system’s own biofeedback model, not as evidence that the device can make several thousand medical diagnoses in a matter of minutes.
The connection with ETDFL
The ETDFL project states in its manuals that its database is being developed in collaboration with 12 clinics that use the Quantum SCIO for bioresonance measurements and use this data to prepare frequency sets for Rife or electrotherapy devices. This describes the methodology of the ETDFL project itself and is important for understanding how their list was created—and continues to be created and updated.
Biofeedback is not a substitute for diagnosis
If a device uses terms such as “scan,” “analysis,” “resonance,” or “biofeedback,” the results should not automatically be equated with a laboratory, radiological, or medical diagnosis. In cases of unexplained symptoms, it makes sense to first use appropriate medical tests to determine what is actually happening in the body, and then to incorporate complementary methods as a supplement.
It is also important to understand that interpreting the results is not straightforward. With systems such as BICOM, Quantum SCIO, and similar devices, the quality of treatment depends heavily on the therapist’s knowledge, experience, and qualifications. Therefore, it is advisable to choose an experienced bioresonance therapist, preferably one with appropriate medical or health-care training, and to avoid lay interpretations of generic computer diagnostic reports.
Zappers and Programmable Generators for Home Use
Home devices generally do not attempt to analyze the user but instead generate an electrical signal that is delivered to the body via handles, wristbands, adhesive electrodes, gloves, or other conductive accessories. The differences between them can be quite significant—ranging from a single frequency to fully programmable frequency generators.
Simple zappers
One or a few preset frequencies. The advantage is simplicity; the limitation is limited flexibility.
Program Cards
The device plays pre-programmed sets from cards or memory. It is easy to use, but the user is limited by the system’s structure.
Free Programming
The user enters frequencies and creates programs independently. This offers the greatest flexibility but requires a better understanding of charts and protocols.
Zaper Zaperino and the Classic Clark Tradition
At the simplest end of the spectrum are devices with one or a few frequencies. The Slovenian Zaper Zaperino, for example, is currently available with settings of 8 Hz and 30 kHz. Classic zappers in the Hulda Clark tradition are typically designed for frequencies around 30 kHz, with a 9-volt battery power supply and a positive-biased square wave signal.
With such devices, high absolute frequency accuracy has historically not been the primary goal. Even today’s suppliers of Hulda Clark-style zappers state that a nominal 30-kHz generator can actually vary quite widely. This is a completely different approach from devices where the user wants to precisely enter a specific value from a frequency list.
Diamond Shield: cards, programs, and a wide range
The Diamond Shield Professional represents an intermediate approach. According to the manufacturer’s manual, it operates at frequencies ranging from approximately 0.5 Hz to 2 MHz, and allows for a positive-offset square wave signal, voltage adjustment, wobble, modulation, and the storage of individual programs on a ChipCard. These cards are one of its distinctive features: a therapist can prepare a program, which the user can then carry out at home.
Zapper-Pro: Direct Frequency Programming
The Zapper-Pro is designed differently: the user enters frequencies directly into the device and can change them at any time. Two versions are available. The first version supports frequencies from 1 Hz to 1 MHz, multiple program slots with sets of ten frequencies each, and additional slots for longer-duration, single-frequency operation of up to 9 hours. The device is therefore particularly well-suited for use with frequency lists such as the ETDFL, as the user is not restricted to pre-set programs.
This version can be supplemented with the 11-HRF add-on, which adds the 11th harmonic to the base frequency in a phase-synchronized manner. The other model, the Zapper-Pro with a built-in 11-HRF output, already has this function integrated into the device itself. Thus, the system allows for the use of fundamental frequencies ranging from 1 Hz to 1 MHz and the corresponding 11th harmonic, thereby extending the frequency range to 11 MHz, or 11 million Hz.
When using 11-HRF, a combination of two different electrodes—or two transmission modes—is typically employed: one electrode transmits the fundamental frequency, while the other transmits its 11th harmonic. The purpose of this design is to simultaneously utilize the fundamental and harmonic components of the frequency signal.
The Zapper-Pro features analog outputs, a square wave signal with a positive offset, and a stable power supply via a 12-V adapter or mini UPS.
An important practical difference
If you wish to use a specific frequency list, check whether your device allows you to enter actual numerical frequencies. With some systems, you can view and adjust each frequency; with others, you only select program names; and with still others, the frequencies or algorithms are proprietary to the manufacturer.
Computer- and Phone-Controlled Systems
Spooky2: Exceptional Software Flexibility
Spooky2 is a good example of a system where the software is the central component. The manufacturer offers a free Windows program and several types of hardware and application methods: contact output, plasma, PEMF, laser, and other accessories. The software library contains a large number of predefined frequency sets, and users can also create their own.
Due to its modularity, Spooky2 is technically very flexible, but this also makes it more challenging to use. It makes particular sense to distinguish between methods involving direct physical energy transfer—electrode, coil, light, or plasma output—and their so-called “remote” counterparts, whose mechanism of remote action is not comparably well-established in biophysics or clinical medicine.
Healy: Microcurrent, Application, and Custom IMF Programs
Healy is not a classic Rife generator. It is a small, wearable device controlled by a smartphone that delivers Individualized Microcurrent Frequency (IMF) programs via electrodes. Healy also features various application modules for program selection or “resonance” analysis.
It is important to note the manufacturer’s own clarification: their wellness IMF programs are intended to support well-being and “harmonize the bioenergetic field” and are not intended to diagnose or treat diseases. Healy also states that its broader bioenergetic explanations have not been confirmed by independent studies. This places it in a different category from the classic programmable Rife generator.
The advantage of an app—and its limitation
Control via a phone or computer can be very convenient: it allows for large databases, quick searches, data storage, and easy updates. However, the application itself says nothing about the quality of the device’s actual electrical output. The software environment and the output electronics are, in fact, two separate things.
With some solutions, the differences between the software-set frequency and the actual output frequency can be significant, and signal instability, frequency deviations, or distortion of the output waveform may also occur. Therefore, a large program library or a modern user interface does not necessarily guarantee an accurate and stable electrical signal.
In a serious technical comparison, it therefore makes sense to check not only the software but also the actual measured frequency, signal stability, output waveform, voltage, and other parameters of the output electronics.
Plasma emitters, PEMFs, and other field-generating devices
With contact electrodes, electric current flows through contact with the skin. With devices that generate a field, the approach is different. Energy can be coupled via an electromagnetic or magnetic field, or via a high-frequency-excited plasma tube.
Resonant Light PERL: the plasma approach
The Canadian company Resonant Light Technology has been developing devices in the Rife/Bare tradition since 1996. Their current PERL model uses an argon plasma tube and a separate ProGen frequency generator. The manufacturer specifies a frequency range from 1 Hz to 1 MHz and transmission into the surrounding space without the need for the user to hold the contact electrodes at all times.
This is a practically significant difference: a plasma system does not function in the same way as a contact zapper. In the plasma system, the carrier or high-frequency component, the modulation method, and the characteristics of the plasma emitter are important. Therefore, it does not make sense to simply compare the fact that “both use 728 Hz” and conclude that the output is the same.
PEMF: Pulsed Electromagnetic Field
PEMF, or pulsed electromagnetic field, uses a coil through which a time-varying current flows, thereby generating a varying magnetic field. There are both wellness devices and regulated medical systems. The U.S. FDA, for example, classifies certain non-invasive bone growth stimulators that use electric, magnetic, or ultrasonic fields as medical devices for specific orthopedic indications.
F-Gen and Tor-Gen: contactless frequency transmission
The Zapper-Pro system also includes options for contactless frequency transmission. Tor-Gen operates in conjunction with the Zapper-Pro, which generates the selected frequency signal, while Tor-Gen transmits it via a pulsed magnetic field or, according to the manufacturer’s design, a torsion field. The F-Gen is a standalone device that uses a pulsed magnetic field and has built-in frequencies of 1.2 Hz and 7.83 Hz, as well as Solfeggio frequencies.
The advantage of this method is that it does not require direct contact between the electrodes and the skin during use. The F-Gen and Tor-Gen therefore represent a different method of transmitting the frequency signal than the classic Zapper-Pro contact electrodes.
When a “frequency device” becomes a standard medical device
TENS also uses electrical pulses with adjustable frequency and pulse width to manage certain types of pain. An even more striking example is Tumor Treating Fields (TTFields), where a regulated medical device generates alternating electric fields with specific parameters. In February 2026, the FDA approved Optune Pax for certain patients with locally advanced pancreatic cancer in combination with chemotherapy.
The term “frequency” therefore does not in and of itself indicate whether we are referring to a contact device, a plasma emitter, a PEMF system, an experimental Rife system, or a regulated medical technology. The differences lie in the physics of the output, the mode of transmission, the intended use, measurability, clinical data, and regulatory status.
What actually determines the quality of a frequency generator?
When comparing devices, people often look only at the maximum frequency or the number of programs. Technically, this is insufficient. Several characteristics are important simultaneously for describing the output.
1. Frequency range and resolution
The range indicates which frequencies the device is capable of generating, while the resolution indicates the smallest increments in which they can be adjusted. Greater decimal resolution does not, in and of itself, necessarily mean higher quality or greater operational precision. What is most important is that the device reliably reproduces the frequencies for which it is designed and that the output signal is stable and technically sound.
As an example, we can consider the ETDFL frequency list, which is based on many years of development and verification of frequencies as part of an international project. For frequencies listed in Hz, whole numbers are used, while frequencies listed in kHz may also include decimal places. For example, a frequency of 12.34 kHz means exactly 12,340 Hz—which is, again, a whole number in Hz. What matters, therefore, is not the number of decimal places on the display, but rather that the device actually generates the selected frequency accurately, stably, and without significant deviations or distortion of the output signal.
2. Accuracy and Stability
As noted in the previous point, a good device must maintain the set frequency stably. This is influenced by the quality of the reference oscillator, the electronic components, temperature, power supply, and the design of the output stage. Ideally, accuracy should be described in terms of tolerance or a measured value, not just with the marketing term “precision.”
3. The quality of the output signal is important
Frequency devices can generate signals in various ways—using analog oscillators, digital circuits, DDS generators, or other electronic solutions. The method of signal generation alone does not determine the actual quality of the device’s output.
For the user, the most important factors are whether the device actually reproduces the set frequency accurately and stably, what the waveform is like, how the signal behaves under real-world load, and whether its characteristics change during operation.
4. Battery or AC adapter?
The power supply method alone does not determine how well the device will perform. What matters most is that the device receives a stable and adequate supply voltage and that its electronics are designed to maintain a stable output signal even under real-world conditions.
Take the Zapper-Pro, for example, which is designed for a 12-volt power supply and can operate via a suitable AC adapter or a 12V mini UPS. The mini UPS provides an electrically isolated and portable power source, while the adapter ensures uninterrupted operation without worrying about battery capacity.
In simpler electronic circuits that operate, for example, on a 9V battery, a change in the supply voltage can affect the generated frequency, amplitude, or signal waveform. Therefore, when comparing devices, it is more important—beyond the simple question of “battery or adapter?”—to verify whether the frequency, output voltage, and waveform remain stable throughout the entire intended operating range.
5. Sine, square, and sawtooth signals
Different waveforms have different electrical and spectral properties. A sine wave is spectrally the purest and consists primarily of the fundamental frequency, while an ideal square wave contains odd harmonics in addition to the fundamental frequency. A sawtooth wave contains a broader spectrum of harmonics.
In zapper devices, a square-wave signal is therefore often used, as its rapid transitions and the presence of harmonics allow for a more effective form of electrical stimulation than a pure sine wave. For this application, the square-wave signal is often the most suitable choice, though there are, of course, other ways to use it.
6. Positive Offset
In the Clark zapper tradition, a positively offset square wave is very characteristic, in which the voltage generally does not enter the negative range. This design is also used in some modern zappers, including the Diamond Shield and Zapper-Pro. However, a positive offset is not a universal rule for all forms of electrostimulation: numerous medical devices also intentionally use biphasic or alternating pulses, which are generally used under medical supervision.
Do not judge a device by just one feature
“Analog,” “digital,” “positive,” “square,” “1 MHz,” or “10,000 programs” are merely individual characteristics of the device. A good technical description should show how these features work together, what kind of signal the user actually receives at the outputs, and what types of electrodes and accessories can be connected to them.
When making a selection, it makes sense to look for an easily programmable device with the widest possible usable frequency range that generates the selected frequencies accurately, stably, and with minimal distortion. For zapper devices, the appropriate waveform is also important—preferably a square wave with a positive offset.
Just as important as the electronics themselves is post-purchase support. High-quality assistance with using the device, clear instructions, and the ability to get quick answers to questions can significantly impact the user experience. Responsive and reliable service is also important, as it ensures a quick resolution in the event of a malfunction or technical issues and minimizes downtime.
Electrodes and Accessories: How Does the Signal Actually Reach the Body?
Even the most precise generator requires an effective method of transmission. With contact devices, the result is strongly influenced by the contact between the electrode and the skin. Therefore, the type of accessories is not merely a matter of comfort.
Types of Electrodes and User Contact
In contact devices, signal transmission quality is influenced not only by the electronics but also by the type of electrode and the quality of contact with the skin. The electrode material, the size of the contact surface, the pressure applied, skin moisture, and the method of attachment are all important factors.
From an electrical standpoint, copper electrodes have a clear advantage due to copper’s very high conductivity. Its low electrical resistance enables efficient signal transmission with minimal losses within the electrode itself. In practice, however, the total electrical path is also significantly determined by skin contact, the size of the contact surface, pressure, and the condition of the electrode surface.
Carbon or conductive rubber electrodes have significantly higher material resistance than copper, and their actual conductivity depends on their composition, the amount of conductive filler, and the manufacturing method. Their main advantages lie in their flexibility, comfort, and the ability to create larger contact surfaces.
Conductive gloves, socks, wristbands, straps, and self-adhesive electrodes allow for a different mode of contact and can increase or redistribute the contact area. They are particularly practical for longer sessions or when you want to place electrodes on different parts of the body.
When comparing devices, it is therefore not only important what kind of signal the device generates, but also what types of electrodes it supports and how effectively the signal can be transmitted to the user.
Coils, plates, and plasma tubes
In PEMF (Pulsed Electromagnetic Field) systems, an electrical signal flows through a coil, which generates a pulsed magnetic field. Direct contact between the electrode and the skin is therefore not necessary, as the device operates via the field generated in the space surrounding the coil. The frequency and pulsation mode of the magnetic field depend on the electrical signal used to drive the coil.
Some devices also use various plates or combinations of coils and plates to shape or direct the field. The term “scalar plate” is used primarily in alternative frequency systems; therefore, with these devices, it is more important to verify what kind of electromagnetic or magnetic field the device actually generates than to focus on the name itself.
Plasma systems use a different approach: the electrically excited gas in a plasma tube acts as a transmitter of an electromagnetic signal into space. Therefore, direct electrical contact with the user is not necessary in these systems either.
Harmonics and the 11th harmonic resonance frequency
Harmonics are a very real phenomenon in signal processing: if the fundamental frequency is f, its harmonics are the integer multiples 2f, 3f, 4f, and so on. A square wave naturally contains several of them, but with a specialized generator, individual harmonics can be generated and controlled separately.
In the field of frequency research, the 11th harmonic has received special attention, partly due to Anthony Holland’s experimental work with modulated or pulsed fields and cell cultures.
11-HRF in Zapper-Pro
The 11-HRF system is designed so that the Zapper-Pro simultaneously generates the selected base frequency and its 11th harmonic in phase synchronization. The base frequency and its 11th harmonic are then available at separate outputs, allowing for their simultaneous use. The system is available in two versions: as the Zapper-Pro with an additional 11-HRF module, or as a device with the 11-HRF function already integrated into a single housing.
For the Therapist
Important factors include training, a biofeedback environment, documentation, the ability to customize treatments, and a clear distinction between complementary testing and medical diagnostics.
For the advanced home user
The most important factors are programmability, a sufficiently wide range, user-friendly programs, stable output, high-quality electrodes, and compatibility with the selected frequency list.
For the beginner
A simple interface, clear instructions, and good support are often more important than hundreds of settings, modulation options, and add-ons that the user will never use.
Sources and Recommended Reading
In our comparisons, we gave priority to official technical data from manufacturers as well as regulatory and expert sources. When manufacturers make claims about bioresonance, wellness effects, “remote” operation, or other alternative concepts, it is important to distinguish between product descriptions and independent clinical validation.
REGUMED – BICOM. History of the system since 1987, current models, and technical specifications of the BICOM Optima. History · BICOM optima
SCIO International / Biosyn QS. Official presentation of the system, the biofeedback approach, and the renaming of the SCIO product line to Biosyn QS. Read source
ETDFL. Project manual detailing the collaboration of 12 clinics and the use of Quantum SCIO in the preparation of frequency sets. Read source
Healy World. Frequency Applications Guide and terms of use for applications: microcurrent IMF programs, purpose, and limitations of wellness/bioenergetic claims. Manual · Terms
Spooky2. Official presentation of the software-controlled system, contact modes, plasma, PEMF, and other hardware. Read source · Manuals
Diamond Shield Professional. Technical specifications, frequency range, square signal, positive offset, modulation, wobble, and ChipCard system. Read source · Manual
Resonant Light Technology – PERL. Official presentation of the plasma transmitter, frequency range, and system development since 1996. PERL · History
Zaper Zaperino. Current presentation of a simple home device with 8 Hz and 30 kHz as an example of a system with a small number of fixed settings. Read source
Clark Zapper. Example of a classic 30 kHz zapper, positive offset, square signal, and 9-V battery approach in the tradition of Hulda Clark. Read source
Zapper-Pro. Current data on frequency range, programming, and the 11-HRF system. Zapper-Pro · 11-HRF
NHS – TENS. Overview of transcutaneous electrical nerve stimulation, use of electrical pulses, and safety limitations. Read source
U.S. FDA – Non-invasive bone growth stimulators. Regulatory classification of devices that use electrical, magnetic, or ultrasonic fields for specific orthopedic indications. Read source
U.S. FDA – Optune Pax. Approval of Tumor Treating Fields for certain adult patients with locally advanced pancreatic cancer, February 2026. Read source
Schöni MH, Nikolaizik WH, Schöni-Affolter F. Efficacy trial of bioresonance in children with atopic dermatitis. Randomized double-blind study, which in this indication did not show an additional effect of bioresonance therapy compared to the sham procedure. Read source
Health disclaimer: the article compares the technical and user characteristics of very different devices. The mention of a device or its manufacturer’s description does not imply endorsement of all health claims associated with the product. Bioresonance, Rife, zapper, plasma, PEMF, and microcurrent systems differ in purpose, regulatory status, and level of clinical evidence. When diagnosing or treating diseases, consult a physician or appropriately trained healthcare professional. When performing electrical stimulation, follow the manufacturer’s instructions and contraindications, especially in the case of pacemakers or implanted electronic devices, pregnancy, epilepsy, and other conditions listed in the instructions of each device.