Overview
The TEC1-12706 is a thermoelectric (Peltier) module: pass DC current through it and one face gets cold while the other gets hot. No refrigerant, no compressor, no moving parts — just 127 semiconductor couples sandwiched between two 40 x 40 mm ceramic plates. Reverse the polarity and the hot and cold sides swap, which makes it equally useful for cooling and precision heating.
Makers use it for mini fridges, drink coolers, dehumidifiers, camera and laser cooling, temperature-controlled enclosures, and thermal experiments with Arduino, ESP32, or Raspberry Pi control. It is a simple two-wire device electrically — the engineering is all thermal: the hot side must have a real heatsink and fan, or the module will cook itself within a minute at full power.
At a Glance
Rated Voltage
12V DC
Max Current
~6 A
Max Temp Differential
~66-68 °C
Size
40 x 40 x 3.8 mm
Couples
127
Connection
2 wires (red +, black −)
Specifications
| Parameter | Value |
| Model | TEC1-12706 (127 couples, 6 A class) |
| Rated Voltage | 12V DC (Vmax ~15V) |
| Max Current (Imax) | ~6 A |
| Max Cooling Power (Qmax) | ~50-60 W |
| Max Temperature Differential (ΔTmax) | ~66-68 °C (at zero heat load) |
| Operating Range | -30 °C to +70 °C ambient (solder limit ~138 °C) |
| Dimensions | 40 x 40 x 3.8 mm, sealed edges |
| Leads | Red (+) and black (−), ~30 cm |
| Typical Draw at 12V | 4-5 A (supply should provide 6 A headroom) |
| Polarity Behavior | Reversing swaps hot and cold faces |
Wiring & Power Guide
Electrically this is the simplest part you will ever wire: red to +12V, black to ground. Everything that matters is about how much current flows and where the heat goes:
| Module Lead | Connects To |
|---|---|
| Red (+) | +12V from a supply rated 6 A or more (via switch, relay, or MOSFET) |
| Black (−) | Power supply ground (shared with your microcontroller's GND if switched electronically) |
To control it from an Arduino, ESP32, Pico, or Raspberry Pi, switch the 12V line with a logic-level power MOSFET (e.g. IRLZ44N, IRLB8721) or a relay. The GPIO drives only the MOSFET gate — the Peltier's current never touches your microcontroller.
Warning: Never run the module without a heatsink and fan on the hot side. The hot face must shed both the pumped heat and the ~50 W of electrical power; without a heatsink it reaches destructive temperatures in under a minute, and the internal solder can melt.
Note: With the red lead on +, the labeled (printed) face is typically the cold side on these modules — verify with a quick 5V test touch before final assembly. Use thermal paste on both faces and clamp the module evenly.
Tip: Avoid slow on/off PWM directly on the module — thermal cycling shortens its life and ripple hurts efficiency. For proportional control, use high-frequency PWM (>1 kHz) through the MOSFET, or better, vary the DC voltage with a buck converter. Simple bang-bang control with a few degrees of hysteresis is fine for coolers.
Code Examples
Arduino: thermostat-style control via MOSFET
peltier_thermostat.ino
// TEC1-12706 bang-bang control with hysteresis.
// Wiring: MOSFET gate -> D9 (through ~220R), Peltier red -> +12V,
// Peltier black -> MOSFET drain, MOSFET source -> GND (shared with Arduino).
// Replace readTempC() with your sensor (DS18B20, thermistor, etc.).
const int MOSFET_PIN = 9;
const float TARGET_C = 10.0; // desired cold-plate temperature
const float HYSTERESIS = 2.0; // degrees of swing allowed
float readTempC() {
// TODO: replace with a real sensor read
return analogRead(A0) * 0.1; // placeholder
}
void setup() {
pinMode(MOSFET_PIN, OUTPUT);
digitalWrite(MOSFET_PIN, LOW);
Serial.begin(9600);
}
void loop() {
float t = readTempC();
if (t > TARGET_C + HYSTERESIS) {
digitalWrite(MOSFET_PIN, HIGH); // cool
} else if (t < TARGET_C - HYSTERESIS) {
digitalWrite(MOSFET_PIN, LOW); // rest
}
Serial.print("Temp: ");
Serial.println(t);
delay(1000); // slow loop = gentle cycling
}
Pico / ESP32 (MicroPython): high-frequency PWM power limiting
peltier_pwm.py
# TEC1-12706 proportional power via logic-level MOSFET
# Gate -> GP15 (Pico) or GPIO 15 (ESP32); grounds shared.
# 5 kHz PWM avoids audible whine and slow thermal cycling.
from machine import Pin, PWM
import time
tec = PWM(Pin(15))
tec.freq(5000)
def set_power(percent):
"""0-100% of full cooling power."""
duty = int(65535 * percent / 100)
tec.duty_u16(duty)
# Ramp up gently, hold, then off
set_power(30)
time.sleep(10)
set_power(60)
time.sleep(10)
set_power(0)
Frequently Asked Questions
Which side gets cold?
With red on + and black on −, the printed/labeled face is typically the cold side. Confirm with a brief low-voltage test (5V for a few seconds) before mounting — reversing the wires swaps the faces.
What power supply do I need?
A 12V supply rated for at least 6 A per module. At full tilt the module draws 4-5 A; undersized supplies sag, overheat, and give poor cooling. Laptop-style 12V/6A bricks or bench supplies work well.
Can it freeze water?
Yes — with a good hot-side heatsink and fan, the cold plate drops well below 0 °C. The ΔT is what's fixed (~66 °C max at no load), so the colder you keep the hot side, the colder the cold side gets.
Why does my module barely cool even at full power?
Almost always hot-side management: heatsink too small, no fan, missing thermal paste, or uneven clamping. The hot side must dissipate ~100 W (pumped heat + electrical input) — a CPU-class heatsink with a fan is the right scale.
Is PWM bad for Peltiers?
Low-frequency on/off cycling (seconds) stresses the module thermally, and heavy current ripple reduces efficiency. Use high-frequency PWM (>1 kHz), a filtered/buck supply, or hysteresis control with slow, gentle cycles.
Can I use it to heat instead of cool?
Yes — reverse the polarity and the faces swap roles. Peltiers are actually more efficient as heaters (COP > 1), which is why they appear in temperature-cycling and incubator projects. Keep the same heatsinking discipline.
Does condensation matter?
Below the dew point the cold side will sweat, and water plus electronics is a bad mix. These modules have sealed edges, but you should still insulate the cold cavity and route drips away from wiring.