Shunt Regulator: 33,0V, 4,0Ω, 9W - Pololu 3776

Index: PLL-13478 EAN: 5904422341800

The shunt regulator can protect the power supplies from voltage spikes generated by the motor controllers connected to them. This version has a fixed value of 33.0 V, a shunt resistance of 4.0 Ω and 12 SMT shunt resistors located on one side of the PCB. An external potentiometer can be used to set the voltage.

Shunt Regulator: 33,0V, 4,0Ω, 9W - Pololu 3776
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Shunt voltage regulator 33.0V - power:
Manufacturer: Pololu

Product description: By-pass voltage regulator 33.0 V, 4.0 Ω, 9 W - Pololu 3776

The shunt regulator canprotectpower suppliesfrom voltage spikes generated bymotor controllersconnected to them. This version has a fixed value of33.0 V, a shunt resistance of4.0 Ωand12SMT shunt resistorslocated on one side of the PCB. An externalpotentiometercan be used toset the voltage.

The regulator should be installed in parallel with thepower supplyfor proper operation. The supply voltage should be lower than the regulator voltage and the regulator should draw only resting current less than 0.5 mA. Any voltage pulses above the setting will cause the regulator to draw significantly more current, dissipating energy and limiting the range of voltage variation.

Shunt voltage regulator 33.0 V, 4.0 Ω, 9 W - Pololu 3776.

Wiring diagram of a shunt regulator between the power supply and the motor controller.

Wiring diagram of the regulator

A simplified schematic of a shunt regulator is shown next. The circuit monitors the voltage and controls theMOSFET, which allows current to flow through the shunt resistance, which sets the maximum current the device can absorb.

Simplified schematic of a shunt regulator.

All Pololu shunt regulators differ only in voltage value and resistance. The available versions can be found in the table below:

13,2 V 26,4 V 33,0 V Fine adjustment LV Fine adjustment of HV
Power: 3 W
32,8 Ω
9 W
1,33 Ω
4,00 Ω
4,00 Ω
15 W
1,50 Ω
2,80 Ω
4,10 Ω
1,50 Ω
4,10 Ω

On the left is the bottom appearance of the 3 W and 9 W regulator, while on the right is the 13 V, 1.50Ω, 15 Wregulator.


The power is primarily intended to indicate the relative average power consumption for a maximum of a few seconds. The boards are designed to clip occasional, short pulses. Prolonged application of voltage above the set point will destroy the regulator almost immediately (in less than a second).

Adjusting the voltage set point

The shunt regulator is available in two adjustable versions with multi-turn potentiometers. All fixed voltage versions can also be adjusted by adding a potentiometer on the board.

The two adjustable versions differ only in the shunt resistance and the mapping optimization of the voltage setting potentiometer.

On the left are the leads for the fixed-voltage regulator, on the right are the leads for the adjustable-voltage regulator.

Schematics of the set voltage relative to the adjusted potentiometer:

LV curve on the left: 1.50Ω, 15 W; HV curve on the right: 4.10 Ω, 15 W.

Diagrams of the adjusted voltage against the adjusted potentiometer

The HV curve was obtained using a 200 kΩ potentiometer with a 33.0 V plate, using a 200 kΩ potentiometer with low voltage constant value plates will disturb the mapping by looking like an LV curve. (100 kΩ or lower value potentiometers can be used at the expense of higher resting current, since the full supply voltage is applied through this potentiometer.)

When setting the voltage with a potentiometer, or to check the exact voltage of any shunt regulator, connect a higher voltage with a current-limiting resistor of at least a few hundred Ω and measure the voltage on the regulator. (Without a current limiting resistor, the regulator would not work if set higher than the test supply voltage and would start to smoke if set below your supply voltage !) Typically, you should set the regulator about 10% above your supply voltage.

Voltage Regulator Specifications - Pololu 3776

  • Output voltage: 33,0 V
  • Shunt resistance: 4Ω
  • Power: 9 W
  • Maximum resting current: 0.5 mA
  • Dimensions: 28.5 x 20.3 x 7.6 mm
  • Weight: 2.8 g

Length 29 mm
Width 21 mm
Height 8 mm
Voltage to 33.0 V
Voltage from 33.0 V
Voltage output from 33.0 V
Output voltage to 33.0 V
Current 0.3 A
Stabilizer - Type2 shunt

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