Is the STMicroelectronics L7912CV Voltage Regulator Suitable for a +12V Output?

In summary: The 7912 series are for -12V. The regulator is wired incorrectly, with the input positive with respect to ground, which is causing the output to be the same as the input. This could potentially damage the regulator.
  • #1
c d
7
1
[mod note: thread moved from homework forum]

I have this Mouser voltage regulator

https://www.mouser.com/ProductDetail/STMicroelectronics/L7912CV/?qs=sGAEpiMZZMug9GoBKXZ75xbXFDWiKqpmvrbz5I0HaKg%3D

Wired according to datasheet https://www.mouser.com/ds/2/389/l79-974159.pdf see insert photo.

https://plus.google.com/photos/phot...0/6526650605024626690?authkey=CPTx7ezW74_OiAE

Would expect to see 12 V output. Input is 15.5 V Wired this a couple of times, get same output as input.

Before I go a lot further, am I on the right track? Your thoughts?
 
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  • #2
cd, do you have the red lead going to the negative terminal of the LiPo?

Interpreting your meter reading, is the O/P positive or negative with respect to ground?
 
  • #3
Red goes to positive of lipo and "input" terminal (middle of three wires) of voltage regulator, thanks for asking. btw, "input" is 15.5 V [positive] with respect to ground. Reading the "output" terminal with respect to ground and getting the same...
 
  • #4
Spec sheet calls for a C1 value of 2.2 uF for tantalum, but 10x or more when an electrolytic is used. Probably want to add a back diode across the output, too, but I don't think that's the problem. Negative regulators (more so than positive regulators) have a tendency to exhibit this symptom when under no load or lightly loaded (under 5 mA) conditions.
 
  • #5
Why do you have the input positive with respect to ground on a negative voltage regulator?
 
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  • #6
c d said:
Red goes to positive of lipo and "input" terminal (middle of three wires) of voltage regulator, thanks for asking. btw, "input" is 15.5 V [positive] with respect to ground. Reading the "output" terminal with respect to ground and getting the same...
79XX series are negative regulators. From what you say i'd guess you hooked the battery backwards. Likely it's shot now.

edit - average supernova and i crossed in the mail..
 
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  • #7
The 7812 series are for +12V.
 

Related to Is the STMicroelectronics L7912CV Voltage Regulator Suitable for a +12V Output?

1. What is a voltage regulator?

A voltage regulator is an electronic device that maintains a constant voltage level in a circuit, regardless of changes in input voltage or load. It is often used to ensure that sensitive electronic components receive a stable and appropriate voltage for proper functioning.

2. How does a voltage regulator work?

A voltage regulator typically consists of a voltage reference, a feedback loop, and a control element. The voltage reference sets the desired output voltage, while the feedback loop continuously compares the actual output voltage to the reference and makes adjustments to the control element to maintain a constant voltage level.

3. What are the types of voltage regulators?

There are three main types of voltage regulators: linear, switching, and shunt. Linear regulators use a series pass element to dissipate excess voltage, while switching regulators use a fast switching element to regulate the output voltage. Shunt regulators, on the other hand, use a shunt element to divert excess voltage to ground.

4. Why is a voltage regulator important?

A voltage regulator is important because it ensures that electronic devices and circuits receive a stable and appropriate voltage. Without a voltage regulator, fluctuations in input voltage or load can cause damage or malfunction in sensitive electronic components, leading to costly repairs and replacements.

5. How do I choose the right voltage regulator for my application?

The right voltage regulator for your application will depend on factors such as the required output voltage, maximum current and voltage ratings, and efficiency. It is important to carefully consider these specifications and consult with a knowledgeable engineer or refer to manufacturer datasheets to choose the appropriate voltage regulator for your specific needs.

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