Current Regulator 190 - 400 Vac resistor and two low power potentiometers

Описание: current regulator 190 - 400 Vac resistor and two low power potentiometers

Need to regulate a tiny current — from 1 to 15 mA — at dangerous high voltage between 190 and 400V AC? In this video, I show a simple off-the-shelf passive current regulator, built using only three components:

🔩 Components Used

R = 16.8 kΩ (25 W high-power resistor)

2 × 500 kΩ potentiometers (1 W each, wired in parallel → ~250 kΩ effective)

AC Source: 190–400 V

By combining one fixed resistor with two parallel potentiometers, you get coarse and fine current control without any transistors, ICs, or SMPS circuits. This method is useful for neon lamps, HV LEDs, discharge tubes, test loads, laboratory use, or emergency adjustment when active components are unavailable.

🔩 Components Used

R = 16.8 kΩ (25 W high-power resistor)

2 × 500 kΩ potentiometers (1 W each, wired in parallel → ~250 kΩ effective)

AC Source: 190–400 V

⚡ Current Range Achieved (Approx):

At 190 V → 1 to ~11 mA

At 400 V → 1.5 to ~15+ mA
(depends on pot settings)

How it works & quick numbers:

Pots in parallel: 500k || 500k ≈ 250kΩ (max adjustable resistance).

Total series resistance range (approx): R_total ≈ 16.8k … 266.8kΩ depending on pot setting.

Approximate currents:

With 190 V across R_total: I ≈ 190 / 266.8k ≈ 0.71 mA (pots max) → up to I ≈ 190 / 16.8k ≈ 11.3 mA (pots ≈ 0).

With 400 V across R_total: I ≈ 400 / 266.8k ≈ 1.5 mA (pots max) → up to I ≈ 400 / 16.8k ≈ 23.8 mA (pots ≈ 0).

Target range 1–15 mA is achievable inside these extremes by adjusting the parallel pots (coarse + fine).

⚠️ Safety Warning
High voltage can kill. Use only with isolated supplies, proper enclosures, HV-rated components, fuses, and under professional supervision. Educational and experimental use only.