The Electrothermal MC Series are analog heating controllers that regulate the average power delivered to laboratory resistive loads using a "simmerstat" (energy regulator) principle. Unlike PID or on/off temperature controllers that target a specific setpoint in degrees, the MC Series adjusts the duty cycle of the mains supply—the proportion of time power is on versus off—via a front‑panel rotary knob. This makes them the correct companion for uncontrolled EM series Electromantles, the Electric Bunsen, heating tapes, and heating cords where the operator judges the appropriate heating level visually by the reaction rate rather than by a temperature readout.

Simmerstat / Energy Regulator Principle

• Bimetallic Strip with Pulsed Output: Inside each MC controller, mains current flows through a resistive heating element coiled around a bimetallic strip. As the strip heats, it bends and opens a set of contacts, interrupting the circuit. The strip cools, the contacts re‑close, and the cycle repeats. The front‑panel knob mechanically adjusts the pre‑tension on the contacts, which changes the mark/space ratio (duty cycle) of the output. This is classic "simmerstat" technology—simple, robust, and entirely independent of external temperature sensors.
• Pulse Frequency Indication: The amber "Mantle/Bunsen Heater On" neon lamp pulsates in real time with the duty cycle. At low knob settings the lamp blinks slowly (power is off most of the time); as the knob is turned clockwise the pulse frequency increases; at maximum setting the lamp glows continuously, indicating 100% power delivery. This provides immediate visual feedback without requiring a multimeter.

Model Selection by Power and Voltage

• MC5: 800 W maximum at 230 V (460 W at 115 V). Suitable for small‑volume Electromantles (up to 250 ml flasks) and single heating tapes. Controller weight: 0.42 kg. Dimensions: 130 × 95 × 105 mm.
• MC242: 1800 W at 230 V (1150 W at 115 V). Covers medium‑volume mantles (500 ml to 2 L). Same form factor as MC5.
• MC227: 2300 W at 230 V. Designed for large‑volume mantles (3 L and above) and multi‑element loads. Weight: 0.82 kg. Dimensions: 115 × 120 × 80 mm.
• MC228X1: 1100 W at 115 V—the 115 V equivalent of the MC227 for North American and Japanese laboratory power. Same weight and dimensions as MC227.
• All models consume only 1 W from the mains for the internal heater and indicator lamps.

Installation and Connection

• Rod, Wall, or Bench: A support‑rod clamp at the rear of each controller accepts a standard ½″ (12.5 mm) laboratory scaffold rod. The controller can also be wall‑mounted using the supplied bracket or placed directly on the bench.
• IEC Output Socket: A short mains lead with an IEC socket connects directly to the heating mantle, tape, or cord. For fume‑hood and remote‑operation setups, an accessory extension mains lead is available.
• Operating Limits: The controllers are rated for indoor use at altitudes up to 2000 m, ambient temperatures from 5 °C to 40 °C, and maximum 80% relative humidity (non‑condensing). They are not spark, flame, or explosion‑proof and must not be used in hazardous areas.

Applications

• Temperature control of EM series Electromantles for round‑bottom flask heating
• Power regulation for the Electric Bunsen (BA6101) benchtop heater
• Heat control for laboratory heating tapes and heating cords used in distillations, extractions, and reflux setups
• Any resistive laboratory heating load requiring simple, sensor‑free power regulation up to 2300 W