Voltage regulators (series)

 These are really useful in synths where we need reliable, stable voltages.

 

They come in many packages 

Here is a transistor regulator

It's a TO-92 package

Here is one with a IC package

In synths common operating voltages are 3.3V, 5V and +12V, -12V.

The most common series of voltage regulators is the 78XX series.  

the 7805 is a 5V regulator

The 7812 is a 12V regulator

 

For negative voltages use the 79XX series

 

The 7912 is a -12V regulator 

For building a +/- 15 PSU you will need a
LM7815 +15V Voltage Regulator      LM7815
LM7915 -15V Voltage Regulator      LM7915  

 

 This is a pic of a NLC eurorack PSU.

It uses two regulators

The 7812 is a 12V regulator

The 7912 is a -12V regulator 

 

 

These can handle up to 30V on the input and depending on the package, up to 1A output current.

 

Arduinos, and many other microcontrollers use 3.3V

 

The LD1117V33 voltage regulator, is a low drop positive regulator with a 3.3V fixed output voltage. 

Making a 5V regulator is very useful in the Euro world.

It's easy too.

Below is a LM7805 voltage regulator.
Notice the two decoupling capacitors:
The capacitors are placed between the power line & ground.  

 

 

The 0.33uF helps to smooth out any low-frequency changes in an input voltage. 
The 0.1uF helps to smooth out any of the high-frequency noise at the output.
Combining these two caps helps to deliver a smooth uninterrupted voltage to your circuits.

 

The decoupling capacitors are connected between your power source, whether that’s 5V or 3.3V, and ground. (Generally it's recommend to use a 100nF ceramic capacitor and a larger 0.1-10uF electrolytic capacitor for each integrated circuit). 

 

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Shunt Regulators

The other type of voltage regulator they you may come across is a shunt voltage regulator.

The main difference between a series and a shunt is how they are connected to the load.

 

 A series regulator is connected (as the name implies) in series with the load to stabilize the regulator's output voltage. 

A shunt regulator, on the other hand, is connected in parallel to the load.

 

 

...

 

This is a TL431 shunt regulator.

It's used along with a series 78L05 voltage regulator  in a Midi to CV converter.

MST MIDI to CV Converter - sYNTHROTEK - part 1

 

The TL431  acts almost like a Zener diode except for that the voltage rating of this IC is programmable.