Circuit Wiring Solution: 12

Showing posts with label 12. Show all posts

Saturday, October 18, 2014

12 Volt Battery Guardian Circuit

Dont get caught with a flat battery; this easy-to-build circuit can cut off the power to a 12V fridge or car stereo system if the battery voltages drops below critical level. Electric fridges in vans and 4WDs are a great idea but if you are not careful, they can severely discharge the battery and leave you stranded. Maybe the battery will end up with severe damage as well. The same problem applies if you have a big stereo system and you like to play it without the motor running.

Main features:

Cuts power to load (eg, fridge) when battery voltage drops below a preset level.
10A rating.
Low power drain.
Chirping sound during cut-out.
Flashing LED indication during cut-out.
Automatically reconnects power when battery recharged.

Operation on 12V is fine when the motor is running and battery charge is maintained but if the fridge is allowed to run for too long when the motor is stopped, it can flatten the battery in a relatively short time. This is where the Battery Guardian comes into play. It monitors the battery voltage and disconnects power to the fridge before the battery becomes too flat to allow the engine to be started again.

Parts layout:

PCB layout:

Circuit diagram:

Source: Silicon Chip 6 May 2002

Wednesday, September 3, 2014

Power Supply Variable 1 3V 12 2V 1A Circuit

Power supply circuit to generate output below were variations between 1.3V DC to 12.2V DC with 1A current.
In addition, the power supply circuit is also equipped with over-current protection or shield against belebih flow. Power supply circuit is very simple, but the quality is quite good, made her basiskan regulator IC LM723 is a pretty legendary.

Description:

R2 to set the output voltage. The maximum current is determined by R3, over-current protection circuit inside the LM723 to detect the voltage on R3, if it reaches 0.65 V, the voltage output will be off her. So the current through R3 can not exceed 0.65 / R3 although output short-circuit in his.

C3 and C4 are ceramic capacitors, as much as possible directly soldered to the PCB, this is because the LM723 is prone to oscillation that is not cool.

LM723 works with 9.5V input voltage to 40 V DC and the LM723 can generate its own current of 150mA when the output voltage is not more than 6-7V under input voltage.

Specifications:

Output (value estimated):

Vmin = (R4 + R5) / (R5 * 1.3)

Vmax = (7.15 / R5) * (R4 + R5)

Imax = 0.65/R3

Max. Power on R3: 0.42/R3

Min. DC Input Voltage (pin 12 to pin 7): Vmax + 5

Component List:

B1 40V/2.5A

C1 2200uF (3300uF even better)

C2 4.7uF

C3 100nF

C4 1NF

C5 330nF

C6 100uF

Green LED D1

D2 1N4003

F1 0.2A F

F2 2A M

IC1 LM723 (in a DIL14 plastic package)

R1 1k

R2 Pot. 5k

R3 0.56R/2W

R4 3.3k

R5 4.7k

S1 250V/1A

T1 2N3055 on a heatsink 5K / W

TR1 220V/17V/1.5

Friday, August 29, 2014

How to Make 12 9 Volt DC to DC Converter BD139

This schema is a DC voltage output from a small DC input generate large voltage.It ‘s easy and quick to do, and reducing the value of the Z-diode, the schema can be universally adapted to other output devices of the schema voltages. The give and all diagrams represent a DC converter with 12V battery 9 volt DC input and output.

12-9 Volt DC to DC Converter Circuit Diagram

With the 10V zener diode, as in the diagram, the output voltage is approximately 9.3 volts DC. The supply voltage is used, should always be at least a few volts higher than the Zener voltage. In this example, I have a 12 Volt DC battery to provide regulated 9-volt DC output. Link

Monday, August 18, 2014

12 to 20 W Audio Power Amplifier

Features:

Thermal protection
Low intermodulationa distortion
Low transient intermodulation distortion
Built-in output current limiter
Low input offset voltage
Output stage with low cross-over distortion
SIL power package

Circuit Diagram:

Circuit Diagram