6.1 Electrical Equipment & Facial Machines (High Frequency, Galvanic, LED)
Key Takeaways
- High-frequency direct application produces a germicidal effect useful for acne, while indirect application (current passed through the esthetician's hands) is used for general stimulation and circulation.
- Desincrustation uses the negative pole of galvanic current to saponify and soften sebum before extractions; iontophoresis uses the pole that matches the product's charge to drive ingredients into the skin.
- High-frequency and galvanic current are both contraindicated for pregnancy, pacemakers or metal implants near the treatment area, and epilepsy.
- Red LED light stimulates collagen production for anti-aging, while blue LED light targets acne-causing bacteria.
- Basic electrical safety rules — never use equipment near water, inspect cords and plugs before use, and unplug before cleaning — apply to every device covered in this section.
6.1 Electrical Equipment & Facial Machines (High Frequency, Galvanic, LED)
Quick Answer: New York's 18-hour Electricity and Equipment unit tests three device families: high-frequency current (thermal/germicidal), galvanic current (desincrustation and iontophoresis), and LED light therapy (red for collagen, blue for acne bacteria). Before touching any of them, an esthetician must know basic electrical safety and every contraindication cold — this is one of the most heavily tested technical areas on the written exam.
Electrical Safety Fundamentals
Every electrical facial machine carries real risk if handled carelessly, and the written exam expects candidates to know the baseline safety rules before any device-specific content:
- Never use electrical equipment near water. Wet hands, damp toweling, or a client's steamed, moist skin dramatically increase shock risk. Dry your hands and the client's skin before applying any electrical current.
- Inspect cords and plugs before every use. Frayed cords, exposed wires, or cracked plugs are removed from service immediately — never make do with damaged equipment.
- Unplug equipment before cleaning or servicing it. Never wipe down, disassemble, or change an electrode on a machine that is still plugged into a live outlet.
- Use grounded (three-prong) outlets and avoid overloading a single circuit with multiple high-draw devices.
- Never leave a client unattended while an electrical device is applied to the skin.
These rules apply across every machine covered below. A written-exam question that describes an unsafe setup — for example, plugging in a high-frequency machine with wet hands — is testing this fundamental safety layer, not the science of the device itself.
High-Frequency Current
High-frequency machines produce a rapid oscillating alternating current (sometimes called a Tesla current) that creates a thermal, heating effect in the tissue. It does not cause a muscle contraction the way galvanic or microcurrent can, because the frequency oscillates too quickly for the body to register it as anything but warmth.
Direct (Germicidal) Application
The electrode is applied directly to the client's skin, either bare for a targeted spot treatment or moved across a layer of gauze for a soothing full-face treatment. When applied directly to bare, oily, or blemished skin, sparking at the electrode tip generates ozone and oxygen at the surface, producing a germicidal effect that helps kill acne-causing bacteria. Direct, germicidal application is the standard high-frequency approach for active acne and oily, congested skin.
Indirect Application
The client holds a glass electrode in their hand while the esthetician performs facial massage. Current passes from the machine, through the client's body, and out through the esthetician's hands into the client's face, producing a mild, generalized warming and stimulating effect. Indirect high frequency increases local circulation and glandular activity without ever placing the electrode itself on the face, which makes it useful for boosting product penetration during a massage sequence.
High-Frequency Contraindications
High-frequency current is contraindicated for clients who are:
- Pregnant — the current's effects on fetal development are not established, so it is avoided as a precaution.
- Wearing a pacemaker or living with a heart condition — electrical current can interfere with the device.
- Carrying metal implants near the treatment area (plates, pins, dental implants) — metal conducts current and can concentrate it unpredictably.
- Diagnosed with epilepsy — the current may act as a seizure trigger.
Galvanic Current
Galvanic current is a continuous, direct current with a fixed positive and negative pole. Unlike high frequency, its chemical effect on the skin depends entirely on which polarity is used, which is why exam questions on this topic almost always ask which pole is used for which purpose.
Desincrustation (Negative Pole)
Desincrustation uses the negative pole (cathode) together with a saline or alkaline desincrustation solution on the skin. The negative charge triggers a chemical reaction that saponifies and emulsifies sebum — turning hardened oil in the follicle into a soap-like substance that softens and lifts out more easily. Desincrustation is performed before extractions to prepare congested, oily skin and reduce trauma during manual extraction.
Iontophoresis (Polarity Matches the Product)
Iontophoresis uses galvanic current to drive water-soluble product ions deeper into the skin, following the principle that like charges repel: a positively charged product is driven in using the positive pole, and a negatively charged product is driven in using the negative pole. This lets an esthetician push serums and treatment ingredients past the stratum corneum more effectively than manual application alone.
Galvanic Contraindications
Avoid galvanic treatments, including desincrustation and iontophoresis, on clients who are pregnant, have a pacemaker or metal implants, have epilepsy, or present with inflamed acne, active pustules, or couperose (broken capillary) skin in the treatment area — active current on inflamed or fragile capillaries can worsen the condition.
LED Light Therapy
LED (light-emitting diode) devices deliver specific wavelengths of light at low, non-thermal energy levels. Unlike high-frequency or galvanic current, LED does not rely on an electrical current passing through the skin.
| Light Color | Wavelength Range | Primary Esthetic Use |
|---|---|---|
| Red light | ~630–700 nm | Stimulates fibroblast activity to boost collagen and elastin production; used for anti-aging and overall skin rejuvenation |
| Blue light | ~405–420 nm | Targets and helps destroy acne-causing bacteria in the follicle; used for active breakouts |
LED safety: clients and estheticians should wear proper eye protection during treatment, and clients on photosensitizing medications should be screened before the service. Because LED is low-energy and non-thermal, it is one of the gentlest machine-based treatments an esthetician performs and carries far fewer contraindications than high frequency or galvanic current.
Other Common Facial Machines (Quick Reference)
| Machine | Primary Function |
|---|---|
| Magnifying lamp | Illuminated, magnified close-up view of the skin for analysis and precision work such as extractions |
| Steamer | Warms and hydrates the skin to soften debris and prepare for extraction (full protocol covered in Section 6.2) |
| Brush/rotary machine | Rotating bristle head used for mechanical exfoliation and deep cleansing |
| Vacuum/suction machine | Handheld suction tip that loosens and lifts surface debris and blackheads while boosting circulation |
| Microcurrent | Very low-level current that mimics the body's natural bioelectric signals to tone and lift facial muscles |
Matching a described symptom or client goal — active pustular acne, a desire for deeper product penetration, anti-aging without heat — to the correct device and correct application method is the core skill tested in this content area.
A client with active, inflamed acne wants a high-frequency treatment. Which application method produces a germicidal effect that helps address acne-causing bacteria?
Which galvanic technique uses the negative pole to soften and emulsify sebum before extractions?
Which of the following is a contraindication shared by both high-frequency and galvanic current treatments?