Voltage regulators (stabilizers) 78xx and 79xx. Redakce HW serveru, May – As a preface, I would like to say that HW server does not indend at all. LM79XX Series. 3-Terminal Negative Regulators. General Description. The LM79XX series of 3-terminal regulators is available with fixed output voltages of − 5V. 79xx voltage regulators are very commonly used in electronic Similar to IC 79xx, IC 78XX is a three pin IC that gives a constant output voltage.

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Each type reulator internal current limiting, thermal shut down and safe operating area protection, making it essentially indestructible. This is used to prevent bots and spam. Voltage regulator IC can be defined as 79xc 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.

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Current consumptions of both stabilizers, with and without a load. Any of the other positive regulators will work the same way as long as one observes proper input voltage levels and component ratings. As a supply, we have used a BS DC power supply and a transformer with one-way rectifier. Again, we do apologize to GM Electronic for releasing this information.

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Tomas Kouba Jan Rehak Translated by: The ST stabilizer is clearly distinct. No data is shared unless you engage with this feature. After a closer examination, I have found V at its reference input, instead of expected -8V. The internal schematics of 79xx and 78xx are very different you can see both internal schematics in datasheets, which are included at the end of this article. This article needs additional citations for verification.


Consumption no load Consumption 1k load LCV 1.

Conclusion is, that oscillations are not the cause of our overvoltage problem. Possible cause of the problem: If adequate heat sinking is provided, they can deliver voptage 1A output current. The whole thing worked about a year or so. This 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.

The fault is definitely caused by ST, the manufacturer. Figure 2 shows the electrical connection for the LM78XX series. If this is an intention to voktage internal consumption of the circuit to a minimum, at the expense of problems with output voltage with no load, it should have been mentioned in the datasheet.

The capacitor C 2 is required for stability. This 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. Regjlator software libraries such as jQuery are loaded at endpoints on the googleapis.

Comments are not for promoting your articles or other sites. Two stabilizers were used for comparison.

The pin 3 acts as the output terminal constant regulated 5V. The 78xx line are positive voltage regulators: Then, we have studied carefully the datasheets.

The rest of this article analyses the fact, that: This is feature allows you to search the site. Views Read Edit View history. For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: This page was last edited on 5 Decemberat Diode D1 was added to compensate for the voltage drop across the base-emitter junction of Q1. Usage of voltage regulator ICs helps in avoiding such events by maintaining voltage at the required levels.


The LM78S40 from Fairchild is not part of the 78xx family and does not use the same design. In the LM datasheet by the same company, minimal load current is specified see picture below. There, they do clearly state that the output voltage is guaranteed in a certain load current range; however, there is NO warning, that a voltage four times higher than the nominal output can appear at the output pin. The comparison is only an example what a developer can buy in an electronics components store.

Otherwise, their input voltage decreased by about 8V appears right at the output. At the very end ofthe Czech subsidiary of ST has informed us that information about this behavior will be included in a future update of the respective datasheets. We 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.

Nothing like that is there. However, components by other manufacturers behave differently. These devices support an input voltage anywhere from around 2.

Using LM78XX Series Voltage Regulators Tutorial

The pin out configuration of IC 79xx is shown in the diagram below. Later we will examine adjustable, regulated power supplies. These devices can be used with external components to obtain adjustable voltages and currents.