LM335 | Electronic Project Circuits

Posts Tagged ‘LM335’

Junk-box Fan Speed Controller using lm335

My new home theatre receiver was getting rather hot in the close confines of its cabinet, with the temperature reaching over 40°C after only about 30 minutes of use. To help lower the temperature, I decided to install a fan in the cabinet. A 75mm hole was cut in the shelf under the receiver, and a 12V fan salvaged from an old computer power supply was mounted underneath. The fan was powered from a 12V DC plugpack. This did the job, keeping the temperature below 30°C even after prolonged use on a warm day. However, the fan was annoyingly loud when running at full speed. To reduce the noise level substantially, I built this fan speed controller with temperature feedback.

The circuit was culled from variety of ideas found on various sites on the internet, with the final circuit designed from what was in the “junk box”. Air temperature in the cabinet is sensed via an LM335 (TS1). It is glued to a piece of aluminium about 25mm square with instant glue, which is then attached to the top of the receiver with “Blue-Tack”. About 300mm of audio coax makes the connection back to the circuit board. The LM335’s output rises 10mV per degree Centigrade. It is calibrated to zero output at -273°C, so at 20°C, the output will be 2.93V. This is applied to the non-inverting input of a 741 op amp (IC1).

Source link:http://www.extremecircuits.net/2010/06/junk-box-fan-speed-controller_18.html

Be the first to comment - What do you think? Posted by admin - May 28, 2011 at 6:05 pm

Categories: Motor controller Tags: Fan Speed Controller, LM335

Simple LM335 Thermometer

I’ve been fascinated by the LM335 for some time -maybe my obsession with stability finally gave way to my fascination with a circuit with intentional thermal drift. I finally bought some the other day, and to check one out, I hooked it up as a thermometer, based the National Semiconductor application note.

The circuit consists of two parts: The LM335 and its adjustment. The output of the LM335 is 10 millivolts per degree C, with 25 degrees C corresponding to 2.982 VDC. A reference circuit provides a zero reference voltage. It is adjusted to (2.982 volts – (25 degrees x 10 millivolts/degree) = 2.832 volts. To read the temperature of the LM335 directly in degrees C, connect the + lead from a high impedance DVM to the output pin and the – end of the DVM to the 2.732 volt pin.

The factor of 10 millivolts per degree C is equivalent to 10 millivolts per degree K, since a change of one degree C is equal to a change of one degree K. The difference in the two scales is only their offsets. The melting point of water ice is 0 degrees C and 273.15 degrees K. The boiling point of water is 100 degress C and 373.15 degrees K.

Read More Source:http://www.cappels.org/dproj/lm335th/LM335thermometer.html
Thank you.

Be the first to comment - What do you think? Posted by admin - August 10, 2007 at 11:03 pm

Categories: Basic electronics, Electronic Control, Meter Tags: LM335, temperature-meter

Digital Measurements Temperature by LM335

Here is circuit Digital Measurements Temperature by IC LM335,
IC LM335Z (TEMP SENSOR) volt at IC 2.73V, 10mV : C
VR1 adjustable temp.
This circuit for IC ICL7107 display temp by LED 7 Segment.

Circuit Digital Measurements Temperature by LM335

PCB Digital Measurements Temperature by LM335