Datasheet

LM78M05CMWC Datasheet PDF – 5V, Voltage Regulator

Posted on by pinout

Part Number: LM78M05CMWC

Function: 3-Terminal Positive Voltage Regulator

Package: TO-220, TO-252, and PFM D-PAK Type

Manufacturer: Texas Instruments

Image

LM78M05CMWC datasheet pdf

 

Description

The LM341 and LM78M05CMWC, LM78M05 series of three-terminal positive voltage regulators employ built-in current limiting, thermal shutdown, and safe-operating area protection which makes them virtually immune to damage from output overloads. With adequate heatsinking, they can deliver in excess of 0.5A output current. Typical applications would include local (on-card) regulators which can eliminate the noise and degraded performance associated with single-point regulation.

Key Features

  • Fixed 5V output voltage
  • Output current capability > 0.5A (with proper heatsinking)
  • No external components required for basic operation
  • Internal thermal shutdown protection
  • Internal current limiting (short-circuit protection)
  • Safe Operating Area (SOA) protection for output transistor
  • Available in multiple fixed voltage variants (5V, 12V, 15V)

Pinout

LM78M05CMWC pinout regulator

Design Considerations

  • Thermal Dissipation: Power loss = (Vin – 5V) × Iout → ensure proper heatsink
  • Dropout Margin: Maintain Vin ≥ ~7V for stable regulation
  • Efficiency: Low compared to switching regulators, especially at high Vin
  • Noise Performance: Very low output noise, suitable for analog circuits
  • Stability: Requires proper bypass capacitors close to pins

Advantages

  • Extremely simple implementation
  • Robust protection features
  • Low noise compared to switching regulators
  • High reliability and wide usage history

Limitations

  • Low efficiency at high input-output voltage differential
  • Requires thermal management at higher currents
  • Not suitable for battery-powered high-efficiency designs
  • Relatively high dropout compared to modern LDOs

Typical Applications

  • Microcontroller and logic supply (5V rail)
  • On-board regulation (point-of-load)
  • Linear post-regulation after DC-DC converters
  • Analog and mixed-signal circuits requiring low noise
  • Industrial and consumer electronics

Alternative / Equivalent Devices

  • LM7805 – Standard 1A version
  • LM1117-5.0 – Low dropout regulator
  • AMS1117-5.0 – Popular LDO alternative
  • TLV1117 – Improved LDO performance
  • DC-DC Buck Converters – For higher efficiency applications

Other data sheets are available within the file:

LM341, LM341T-12, LM341T-15, LM341T-15/NOPB, LM341T-5.0

LM78M05CMWC Datasheet PDF Download


LM78M05CMWC pdf

MQ135 Datasheet PDF – Semiconductor Gas Sensor

Posted on by pinout

The MQ135 is a semiconductor gas sensor widely used for detecting air quality and harmful gases. It belongs to the MQ sensor family, which uses SnO₂ (tin dioxide) as the sensing material.

Function: Gas Sensor

Package: 6 Pin Module type

Manufacturer: Futurlec

Image:

MQ135 datasheet

Description

The MQ135 is a semiconductor gas sensor designed to detect air quality-related gases such as NH3, NOx, alcohol, benzene, smoke, and CO2 equivalents in indoor environments. It employs a heated SnO2 sensing element that offers high sensitivity, wide detection range, and stable response characteristics. This sensor is commonly used in air quality monitors, smart home systems, and environmental sensing projects.

Features

  • Wide detecting scope
  • Fast response and high sensitivity
  • Stable and long operational life
  • Simple drive circuit
  • Wide detection range for indoor air quality monitoring
  • SnO2 semiconductor sensing element
  • Good repeatability and long-term stability
  • Suitable for continuous gas monitoring

Principle of Operation

The MQ-135 sensor works on the chemiresistor principle:

1. Sensing Material: SnO₂ changes its resistance when exposed to oxidizing or reducing gases.

2. Gas Detection: The sensor’s resistance decreases with the presence of target gases.

3. Heater Element: Built-in heater maintains the sensing material at the required working temperature (~200–300°C) to improve reaction and sensitivity.

4. Output Signal: Analog voltage or resistance change, which can be read by a microcontroller ADC or converted to PPM (parts per million) with calibration.

MQ135 Pinout

components

1. Gas sensing : layer SnO2

2. Electrode : Au

3. Electrode line : Pt

4. Heater coil : Ni-Cr alloy

5. Tubular ceramic : Al2O3

6. Anti-explosion network : Stainless steel gauze (SUS316 100-mesh)

7. Clamp ring : Copper plating Ni

8. Resin base : Bakelite

9. Tube Pin : Copper plating Ni

Design Notes

  • Allow an adequate preheating period before taking measurements for maximum accuracy
  • Use a suitable load resistor to optimize sensitivity for the target gas concentration
  • Avoid exposure to silicone vapors and corrosive gases that may damage the sensing element
  • Ensure good airflow around the sensor during operation
  • Periodic calibration is recommended for quantitative air quality measurements

Applications

They are used in air quality control equipments for buildings/offices, are suitable for detecting of NH3, NOx,  alcohol,  Benzene,  smoke, CO2 , etc.

1. Air Quality Monitoring: Indoor/outdoor air quality sensors, smart home air purifiers

2. Industrial Safety: Detecting harmful gases in factories

3. Environmental Monitoring: Measuring urban pollution, CO₂, NOx levels

4. Educational Projects: Used in DIY electronics to demonstrate gas detection

5. Vehicle Emissions Monitoring: Detecting exhaust gases and VOCs

 

Comparison with Other MQ Sensors

Sensor Target Gas Sensitivity Application
MQ-2 LPG, H₂, Methane, Smoke High for flammable gases Gas leak detection, fire alarms
MQ-6 LPG, Butane, Propane High for LPG/Propane Home gas detectors
MQ-7 CO (Carbon Monoxide) High for CO CO detection, air quality
MQ-135 NH₃, NOx, CO₂, Benzene, Smoke High for harmful air gases Air quality monitoring, pollution detection

Other data sheets are available within the file: MQ-135

MQ135 Datasheet PDF Download


MQ135 pdf

List of search results related to this post

Part number Description
MQ-4 Gas Sensor – Hanwei
MQ-5 Gas Sensor – Winsen
MQ6 Gas Sensor
MQ-136 Gas Sensor – Hanwei