IC 79xx (7905, 7912, 7915, 7918) - Negative Voltage Regulator

Updated on May 28, 2018

79xx voltage regulators are very commonly used in electronic circuits. The main purpose of this IC is to supply required regulated negative voltage to the circuits. IC 79xx can supply a constant negative voltage output, in spite of any voltage fluctuations in its input voltage. It can be mainly found in the circuits in which integrated circuits that require +Vcc and – Vcc are used.

IC 7912

What Is a Voltage Regulator IC?

Voltage regulator IC can be defined as an integrated circuit that is capable of supplying a constant controlled output voltage which is not at all affected by the variations in input voltage provided that the variations are within the prescribed limits under specified atmospheric conditions. Voltage fluctuations may damage or reduce the life of circuit components. Usage of voltage regulator ICs helps in avoiding such events by maintaining voltage at the required levels.

IC 79xx

IC 79xx is a three pin negative voltage controller IC. It is a small integrated circuit used in a circuit to supply a constant negative input voltage. The number 79 indicates that it is a negative voltage regulator and xx indicates the output voltage of the IC. ‘xx’ can be replaced by the controlled output voltage provided by the regulator, for example, if it is 7905, then the output voltage of the IC is -5 V. Similarly if it is 7912, then output voltage of the IC is -12 volts and so on. The name of the IC may vary based on the manufacturer as LM79xx, L79xx, MC79xx etc.

IC 79xx requires heat sink for its safe operation. Heat sink boosts heat dissipation therefore the life of the device can be extended.

79xx ICs and Output Voltages

IC Number
Output Voltage
7905
-05 Volts
7912
-12 Volts
7915
-15 Volts
7918
-18 Volts

79xx Pin out Configuration

The pin 1 acts as the Ground terminal (0V). The pin 2 acts as the input terminal (5V to 24V).  The pin 3 acts as the output terminal (constant regulated 5V).
The pin 1 acts as the Ground terminal (0V). The pin 2 acts as the input terminal (5V to 24V). The pin 3 acts as the output terminal (constant regulated 5V).

Pin out Configuration of IC 79xx.

The pin out configuration of IC 79xx is shown in the diagram below.

  • The pin 1 acts as the Ground terminal (0V).
  • The pin 2 acts as the input terminal (5V to 24V).
  • The pin 3 acts as the output terminal (constant regulated 5V).

Connection Diagram

IC 79xx is used in circuits as shown in the circuit. In order to improve stability two capacitors – C1 and C2 are used. The capacitor C1 is used only if the regulator is separated from filter capacitor by more than 3". It must be a 2.2 μF solid tantalum capacitor or 25μF aluminum electrolytic capacitor. The capacitor C2 is required for stability. Usually 1 μF solid tantalum capacitor is used. One can also use 25μF aluminum electrolytic capacitor. Values given may be increased without limit.

79xx Connection diagram

IC 78XX

Similar to IC 79xx, IC 78XX is a three pin IC that gives a constant output voltage of +5V irrespective of the varying input voltages. The maximum value of input voltage that the IC can withstand is 24 volts.

Questions & Answers

    Comments

      0 of 8192 characters used
      Post Comment

      • goodnews11 profile imageAUTHOR

        OSBERT JOEL C 

        5 months ago from CHENNAI

        Approx. 2A max. But the value varies up on manufacturers. Kindly refer the item datasheets for further details.

      • profile image

        herrybarick 

        2 years ago

        hav done my assignment through this sight enx

      • profile image

        MASTEROFTECHNOLOGY 

        2 years ago

        Very useful and easy to understand.Thanks.

      • goodnews11 profile imageAUTHOR

        OSBERT JOEL C 

        4 years ago from CHENNAI

        DDE, Thank you.

      • goodnews11 profile imageAUTHOR

        OSBERT JOEL C 

        4 years ago from CHENNAI

        CyberShelley, Thank you so much

      • DDE profile image

        Devika Primić 

        4 years ago from Dubrovnik, Croatia

        A great insight to this hub so in detail and an educational one. Thank you for following me. Voted up!

      • CyberShelley profile image

        Shelley Watson 

        4 years ago

        Interesting technical article. Voted up, interesting and useful

      working

      This website uses cookies

      As a user in the EEA, your approval is needed on a few things. To provide a better website experience, turbofuture.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

      For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: https://turbofuture.com/privacy-policy#gdpr

      Show Details
      Necessary
      HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
      LoginThis is necessary to sign in to the HubPages Service.
      Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
      AkismetThis is used to detect comment spam. (Privacy Policy)
      HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
      HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
      Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
      CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
      Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
      Features
      Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
      Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
      Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
      Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
      Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
      VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
      PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
      Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
      MavenThis supports the Maven widget and search functionality. (Privacy Policy)
      Marketing
      Google AdSenseThis is an ad network. (Privacy Policy)
      Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
      Index ExchangeThis is an ad network. (Privacy Policy)
      SovrnThis is an ad network. (Privacy Policy)
      Facebook AdsThis is an ad network. (Privacy Policy)
      Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
      AppNexusThis is an ad network. (Privacy Policy)
      OpenxThis is an ad network. (Privacy Policy)
      Rubicon ProjectThis is an ad network. (Privacy Policy)
      TripleLiftThis is an ad network. (Privacy Policy)
      Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
      Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
      Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
      Statistics
      Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
      ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
      Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)