LM339

The LMx39x and the LM2901x devices consist of four independent voltage comparators that are designed to operate from a single power supply over a wide range of voltages. Operation from dual supplies also is possible, as long as the difference between the two supplies is 2 V to 36 V, and VCC is at least 1.5 V more positive than the input common-mode voltage. Current drain is independent of the supply voltage. The outputs can be connected to other open-collector outputs to achieve wired-AND relationships. The LM139 and LM139A devices are characterized for operation over the full military temperature range of –55°C to +125°C. The LM239 and LM239A devices are characterized for operation from –25°C to +85°C. The LM339 and LM339A devices are characterized for operation from 0°C to 70°C. The LM2901, LM2901AV, and LM2901V devices are characterized for operation from –40°C to +125°C.

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Audio VU/Sound Level Meter with LM339

“This is an “Audio VU Meter” or “Sound Level Meter”, it is a general-purpose bar-graph Audio VU meter designed for fun projects. All you need is to hook up one wire to the output of the audio amplifier’s speaker …

Pocket Metal Locator

“Cool little Pocket Metal Locator sensitive enough to identify small nails and tacks in wood with four independent search coils and LEDs. This cool little Pocket Metal Locator is sensitive enough to identify small nails and tacks in wood and …

Universal Battery Charge Indicator 3.7v-24v

“As we all deal with various potential battery e.g 3.7v li-po li-ion battery, 6v 9v, 12v, 24v lead acid battery. It can be charged using its respected chargers but if we want to monitor charge status then we …

Arduino_Inductance_ And_capacitance_meter V 0.1

“A digital electronics component_meter based on arduino, that mesure inductance and capacitance with an lcd menu display ( more options will be added later :) Introductions : Heres a really useful and easy project you can do with an Arduino. If you have …

Pocket Metal Locator - Arduino

“This cool little Pocket Metal Locator is sensitive enough to identify small nails and tacks in wood and compact enough to fit into awkward spaces making it convenient to carry and use for metal locating. The unit has four independent …

Project  The PotLock

The PotLock

“this is a 3 digit combination lock with potentiometers, logic gates and differential comparators”

Eco Friendly Arduino Metal Detector

“Metal Detecting is a lot of fun. One of the challenges is being able to narrow the exact place to dig to minimize the size of the hole left behind.This unique metal detector has four search coils, a color …

Project  multiScope

multiScope

“Fast, Portable and Affordable Oscilloscope and Inductance Meter. Don’t be deceived by its small size. This little beast has an inductance meter and a oscilloscope with sampling rate of 1.7 MS/s, based on a STM32 running at …

Basic Cell Phone Detector

“The basic principle behind this circuit is the idea of using a Schottky diode to detect the cell phone signal.”