hey i am trying to get a thermocouple to connect to ac adc to show temp on 7 segment displays and turn a heater on depending on the temperature. but i have no idea how to get the thermocouple to connect to the adc. anyone have any wiring diagrams to help me out.
hey i need some help with connecting a thermocouple to an adc
- Thread starter nnaselli
- Start date
You may find it easier to use a digital thermometer IC such as LM35, which outputs a voltage directly proportional to temperature. A thermocouple changes resistance with temperature, and you need circuitry to convert that to voltage, and making it linear can be a challenge. For simple thermostat applications, it's probably fine. But I really like the LM35!
Well, you could use the LM34 (Faranheit), although it's harder to find than the LM35 (Celsius). The LM34 reads 0V at 0°F and 0.8V at 80°F. It might not be accurate right down at 0° if you power it only with a single supply. Read the datasheet - it'll answer all.
Well, if your equipment can use the voltages directly from the LM35, eg 15-25°C = 0.15-0.25V, then you're all set. You just need to power the LM35. Also, I've had better luck when I load its output with a 220Ω resistor, at the meter end. Others here have not needed that, so you may want to just experiment. I also recommend using shielded cable if you need the sensor to be very far from the meter, more than a few feet.
