18 Voltage Regulator Kit is an Electronics board that allows you to connect 20 to 24V AC or DC on one side of the board and get 18V DC regulated on the other side. Every lab should have a few of these boards handy. The boards will allow you to easily power all your analog components (i.e. op-amp). The Terminal Block TB connector is included and makes it easy to use. 

 

There are two models, A and B. The main difference between the boards is that model A has a power indicator utilizing Light Emitter Diode (LED) L1. Model B doesn't.

 

     

Model A                                               Model B  

 

Basic operation of the voltage regulator board:

 

The diodes bridge D1-D4, together with the capacitor C1, will convert input AC voltage to DC Voltage (See below kit drawing). Additionally, the diode bridge ensures that the polarity of the bridge output remains the same regardless of the input voltage polarity. It's what we call "dummy-proof." Let's say, for example, the board is powered by a 24V battery, the output polarity remains the same no matter how you connect the power to the board's diodes bridge.

 

The other side of the diodes bridge drives the voltage regulator U1. The voltage regulator is the main component of this kit (regulator). Usually having three legs, it converts varying input voltages and produces a constant regulated output voltage. They are available in a variety of outputs. The most common part numbers of the regulator starts with the numbers 78 or 79, and finish with two digits indicating the output voltage. The number 78 represents positive voltage, and 79 a negative one. The 78XX series of voltage regulators are designed for positive input. And the 79XX series is designed for negative input. The LM78XX series typically has the ability to drive currents up to 1A. Application requirements up to 150mA, 78LXX can be used. As mentioned above, the component has three legs: Input leg which can hold up to 36VDC (we recommend not to exceed 24V), Common leg (GND) and an output leg with the regulator's voltage. For maximum voltage regulation, adding capacitors C2 and C3 in parallel between the common leg and the output is usually recommended. C2 a 0.1MF capacitor is used. This eliminates any high frequency AC voltage that could otherwise combine with the output voltage. See below circuit diagram for the kit.  

 

The LED, see model A below, will indicate that there is voltage after the diodes bridge. The 2.2K Ohms resistor RL determines the LED's brightness and limits the current flow through the LED. To get more lumination (light) from the LEDs, use smaller resistor. Please be advised you should never exceed the LED maximum current limitations. Doing so will result in burning the LED. You should follow the following basic rules: Standard LED will operate on 8 to 20mA and the voltage developed on the LED is about 1.6VDC, therefore:

 

R_Led = (V_after_bridge – V_LED) / 20mA = (V_after_bridge  – 1.6VDC) / 20mA 

 

Again, we recommend that you use slightly a larger resistor to ensure that the current via the LED will not exceed 20mA. Remember, 20mA is generally the maximum current, and typically the LED glows nicely from about 9mA.

 

Final Note: As a general rule the input voltage should be limited to 2 to 3 volts above the output voltage. The LM78XX series can handle up to 36 volts input, be advised that the power difference between the input and output appears as heat. If the input voltage is unnecessarily high, the regulator will overheat. Unless sufficient heat dissipation is provided through heat sinking, the regulator will shut down.  

 

Kit Includes:

  • 7818                  Voltage Regulator   1pc.

  • 0.1MF                 Capacitor             1pc.

  • 47MF                  Capacitor             1pc.

  • 100MF                Capacitor             1pc.

  • 2.2K Ohms           Resistor               1pc. (model A only)

  • Red                    LED                     1pc. (model A only)

  • 1N4001               Diode                   4pc.

  • 4P Terminal Block  Connector            1pc.  (model A only)

  • PCB                                              1pc.

Schematic:  

 

 

Mounting enclosure and Din Rail clip (options)

 

 

Shown above Model A, mounted in enclosure P# EID-1593KBK and Din Rail Clip (options)

 

Note: Use heat-sink (if needed). Additionally, Please be advised wires and transformer are sold as options

 

For our line of transformers click Here 

 

Description and SKU#

Price

Picture

18VDC PS, Input up to 24V DC output  +18V /1A with LED power indicator. (model A)

EID-K-VRG-18VD-L1-ASM Fully assembled

EID-K-VRG-18VD-L1-KIT Kit

 

 

 

 

33.00

 

15.99

EID-K-VRG-XXVD-L1-PCB PCB Only

9.99

 

 

18VDC PS, Input up to 24V DC output  +18V /1A(model B)

EID-K-VRG-18VD-L2-ASM Fully assembled

EID-K-VRG-18VD-L2-KIT Kit

 

 

 

30.00

 

13.98

EID-K-VRG-XXVD-L2-PCB PCB Only

7.95

 

 

Modified Black enclosure

EID-K-1593KBK

  

6.97

 

EID-1427DINCLIP Din Rail Clip

4.24

 

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