Showing posts with label negative. Show all posts
Showing posts with label negative. Show all posts

Wednesday, September 3, 2014

Simple Negative Adjustable Power supply with 7905


Negative

Often we have to adjust the tension of a negative supply and do not have the ideal component hand, this schema in addition to solving this problem, serves up a Power Adjustable Negative. He use the regulator 9v negative, 7905, the envés to use with fixed voltage, we can use it as a variable regulator. The 7905 in this configuration can adjust the output from -5 to-30V with an input of up to-35V. See table below.

Example: Vin = -20 V

RadjVout
33-5,74
100-6,99
330-11,03
680-18,20

Monday, August 25, 2014

Build a Efficient Negative Voltage Regulator Wiring diagram Schematic

How to Build a Efficient Negative Voltage Regulator Circuit Diagram. This simple Efficient Negative Voltage Regulator Circuit Diagram is One v;ay to provide good negative-voltage regulation is with a low-dropout positive-voltage regulator operating from a well-isolated secondary winding of switch-mode schema transformer. The technique works with any positive-voltage regulator, although highest efficiency occurs with low-dropout types. 

Under all loading conditions, the minimum voltage difference between the regulator ViN and VoUT pins must be at least 1.5 V, the LT1086`s low-dropout voltage. Efficient-negative-voltage-regulator Rating: 7.00/10 (23Votes cast)Category: Power Supply Circuits / AC to DC & DC to DCViews: 3Rank: 5One v;ay to provide good negative-voltage regulation is with a low-dropout positive-voltage regulator operating from a well-isolated secondary winding of switch-mode schema transformer. 

 Efficient Negative Voltage Regulator Circuit Diagram


Efficient

The technique works with any positive-voltage regulator, although highest efficiency occurs with low-dropout types. Under all loading conditions, the minimum voltage difference between the regulator ViN and VoUT pins must be at least 1.5 V, the LT1086`s low-dropout voltage.Efficient-negative-voltage-regulatorIf this requirement isn`t met, the output falls out of regulation. 1vo programming resistors, R1 and R2, set the output voltage to 12 V, and the LT1086`s servo the voltage between the output and its adjusting (ADJ) terminals to 1.25 V. 

Capacitor C1 improves ripple rejection, and protection diode D1 eliminates common-load problems. Since a secondary winding is galvanically isolated, a regulator`s 12 V output can be referenced to ground. Therefore, in the case of a negative-voltage output, the positive-voltage terminal of the regulator connects to ground, and the -12 V output comes off the anode of Dl. The ViN terminal floats at 1.5 V or more above ground.