tag:blogger.com,1999:blog-62404696292674079122024-03-13T12:34:44.219+02:00world technicalWorld Financehttp://www.blogger.com/profile/01757977038242858610noreply@blogger.comBlogger5215tag:blogger.com,1999:blog-6240469629267407912.post-79918098437107637452012-02-23T01:40:00.002+02:002012-09-12T17:42:08.803+02:00Test a car battery voltage using LM3914
This circuit uses the popular and easy to find LM3914 IC. This IC is very simple to drive, needs no voltage regulators (it has a built in voltage regulator) and can be powered from almost every source.
This circuit is very easy to explain:
When the test button is pressed, the Car battery voltage is feed into a high impedance voltage divider. His World Financehttp://www.blogger.com/profile/01757977038242858610noreply@blogger.com2tag:blogger.com,1999:blog-6240469629267407912.post-45256270425287185742012-02-21T08:20:00.002+02:002012-09-12T17:42:37.180+02:00Circuit Receiver Battery Low Voltage Alarm
Here is another equally cool low voltage alarm circuit for your glider receiver battery that I've shamelessly stolen from George Steiner's book "A to Z--Radio Control Electronic Journal" (see below). I've modified it to use with small battery packs in R/C gliders. This design has a trigger voltage at about 4.3 volts, and it draws 1mA or less when quiet and about 4mA when buzzing. ThisWorld Financehttp://www.blogger.com/profile/01757977038242858610noreply@blogger.com0tag:blogger.com,1999:blog-6240469629267407912.post-4942145803118913152012-02-19T01:05:00.001+02:002012-09-12T17:42:52.792+02:00POWERING A PROJECT
POWERING A PROJECT
The safest way to power a project is with a battery. Use 4 x AA cells in a holder or a 9v battery if you only want to use the project for a short period of time.
If you want to use a 555 project for a long period of time you will need a "power supply."
The safest power supply is a Plug Pack (wall-wort, wall wart, wall cube, power brick, World Financehttp://www.blogger.com/profile/01757977038242858610noreply@blogger.com0tag:blogger.com,1999:blog-6240469629267407912.post-25157010580106974982012-02-11T16:38:00.000+02:002012-02-11T16:38:28.926+02:00Low-cost solution for the shipment of each of nickel, cadmium, and NiMH batteriesLow-cost solution for the shipment of each of nickel, cadmium, and NiMH batteries
Here is the schematic of a low-cost universal charger for NiCD - NiMH batteries. This circuit is ideal for car use. It has ability to transform a mains adapter for the charger. This can be used to recharge cell phones, toys, video batteries, MP3 players, ... and is selectable charging current. A LED is located in World Financehttp://www.blogger.com/profile/01757977038242858610noreply@blogger.com0tag:blogger.com,1999:blog-6240469629267407912.post-40368634416179548872012-02-11T15:47:00.002+02:002012-02-11T15:49:19.023+02:00circuit activate a relay by means of a hand clapThis circuit is intended to activate a relay by means of a hand clap. Further beats off of the relay. An unusual and interesting feature of this project is running on battery 3V. The sensitivity of the circuit has been intentionally reduced, to avoid the unpredictable operation. Therefore, the clapping of hands will be stronger they need to allow a constant on-off. Q1 acts as an audio amplifier. World Financehttp://www.blogger.com/profile/01757977038242858610noreply@blogger.com0