Dual Output 12 & -12 Voltage DC Regulator Kit is an Electronics board that allows you to connect 14 to 24V AC Center Trace (TC) or +/-14 to 24VDC on one side of the board and get dual regulated voltages, 12VDC and -12VDC  on the other side. Every lab should have a few of these boards handy. The boards will allow you to easily power all your CMOS or Op-Amp components. The Terminal Block TB connector is included and makes it easy to use. 

 

   

 

      Standard Board               With optional high-current configuration

 

Basic operation of the voltage regulator board

 

The diodes bridge D1-D4, together with the capacitor C1-C4, will convert input dual AC voltages to dual DC voltages (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.

 

The other side of the diodes bridge drives the voltage regulators U1 and U2. The voltage regulators are the main component of this kit (regulators). 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 and the LM79XX series typically has the ability to drive currents up to 1A. Application requirements up to 150mA, 78LXX and 79LXX 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 (positive voltage for the LM78XX and negative for the LM79XX). For maximum voltage regulation, adding capacitors C2,C5 and C3,C6 correspondingly in parallel between the common leg and the output is usually recommended. C3,C6 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.

 

Final Note: As a general rule the input voltage should be limited to 2 to 3 volts above the output voltage (LM78XX series) and 2 to 3 volts below the output voltage (LM78XX series). The LM78XX series can handle up to 36 volts input and the LM79XX -36 volts, 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 slinking, the regulator will shut down.

 

Due to the regulator construction difference, use dual heat-sink (if needed), one for the LM78XX, and one to the LM79XX.

 

Kit Includes

  • 7812                  Voltage Regulator   1pc.

  • 7912                  Voltage Regulator   1pc.

  • 0.1MF                 Capacitor             2pc.

  • 47MF                  Capacitor             2pc.

  • 47MF                  Capacitor             2pc.

  • 1N4001               Diode                   4pc. 

  • 3P Terminal Block  Connector            1pc.

  • 4P Terminal Block  Connector            1pc.

  • PCB                                              1pc.

Schematic

 

 

Option

 

Transformer with central tap (CT) configuration, see schematic below.

 

 

12VDC and  -12VDC PS, high current. Input up to +/-24V AC/DC, outputs  +12V /800mA & -12V /800mA

Description and SKU#

Price

Picture

EID-K-VRG-P12V-N12V-01A-ASM Fully assembled

46.00

 

 

EID-K-VRG-P12V-N12V-01A-KIT   kit

34.00

 

12VDC and  -12VDC PS, low current. Input up to +/-24V AC/DC, outputs  +12V /90mA & -12V /90mA

Description and SKU#

Price

Picture

EID-K-VRG-P12V-N12V-XLA-ASM Fully assembled

40.00

 

EID-K-VRG-P12V-N12V-XLA-KIT  kit

32.00

 

EID-K-VRG-PXXV-NXXV-XXA-PCB PCB Only

18.00