DS

As we know now a days the main problem is charging of a cell phone when we haven't electricity . And this problem is getting bigger when we have more than one cell phone. So here is the circuit which can be solve our problem for charging more than One cell phone. This circuit of the double DC cell phone charger was successfully tried. The required voltages for the operating of this circuit is 12V DC from a battery source.The transistor T1 which we are using is PnP transistor.The general purpose of this transistor is power application e.g driver stages.The IC1 (7805) is a voltage regulator ic which we are using in this circuit. Parts List R1 = 0.1 Ohms 2 watt, R2 = 2 Ohms 2 Watt R3 = 3 Ohms 1 watt C1 = 100uF/25V C2 = 0.1 disc T1 = BD140 D1 = 1N5408 IC1 = 7805

Normally cell batteries have a shelf life of 2 to 5 years under normal use . After that time we have to replace them . Nowadays there replacement batteries which are cheap, but these batteries last for much less cost only months. An easy solution is to use batteries in a circuit that requires less current , we can use them for lighting LEDs .  How to Reuse Old Cell Battery for LED lighting 

This is a simple cell phone detector circuit diagram , this is a pocket-size mobile transmission detector or sniffer can sense the presence of an activated mobile cellphone from a distance of one and-a-half meters. So it can be used to prevent use of mobile phones in examination halls, confidential rooms, etc. It is also useful for detecting the use of mobile phone for spying and unauthorized video transmission. Sourced: EFY  Simple Cell Phone Detector Circuit Diagram  

This is a Simple Solar Cell Voltage Regulator Circuit Diagram . This device is designed to be a simple, inexpensive ‘comparator’, intended for use in a solar cell power supply setup where a quick ‘too low’ or ‘just right’ voltage indicator is needed. The circuit consists only of one 5V regulator, two transistors, two LEDs, five resistors, two capacitors, and one small battery. Although a 4-V battery is indicated, 4.5 V (3 alkalines in series) or 3.6 V (3 NiCd cells in series) will also work.   Solar Cell Voltage Regulator Circuit Diagram   The specifications of voltage regulator IC1 are mainly determined by the size and number of the solar cells and the current pull of the equipment connected to the output. Here the low-drop 4805 is suggested but other regulators may work equally well as long as you observe the output voltage of the solar cells. Transistors T1 and T2 are complementary types i.e. one each of the pnp and npn variety.  Although the ubiquitous BC557B (pn...

4.2.5 Silver oxide cell Similar in appearance to mercury cell, silver oxide cell provides a very stable and slightly higher e.m.f., 1.5 volts as compared to 1.35 volts of the mercury cell. Silver oxide cell’s cathode is made of silver oxide, with potassium or sodium hydroxide, both strong alkalis, as the electrolyte. The capacity of the silver oxide cell, size for size, is considerably better than that of the mercury cell.  Silver oxide cell Because silver is expensive, this cell’s application is thus limited for applications where size and stability of voltage is of supreme importance, such as in  watches and hearing aids.

Plant cell anatomy ... a Generalised Plant Cell ... a typical plant cell with ... ... plant cell diagram. alt ... diagram of a plant cell. This is a diagram of a plant ... Plant Cell ... plant cell ... diagram of a plant cell not ...

This cell-phone-controlled audio/ video mute switch is highly useful in automobiles. The circuit automatically disconnects power supply to the audio/video system whenever the mobile handset is lifted off the holder for making or receiving a call. You can use any readily available cell-phone holder with some mi-nor alterations or fabricate it yourself as shown in Fig. 1.  Fig. 1: Proposed cell-phone holder   The circuit is wired around IC LM555 (IC1), the CMOS version of timer NE555, as shown in Fig. 2. IC1 is used as a medium current line driver with either an inverting or non-inverting output. It can sink (or source) current of up to 50 mA only, so take care while handling it. The audio/video system is connected to the circuit via normally opened (N/O) contacts of the relay.   Fig. 2: The circuit of the cell phone-controlled audio/video mute switch   When the cell phone is in its holder, LDR1 does not receive any light from white LED1 and its resistance is high. ...

Description  This device is designed to be a simple, inexpensive ‘comparator’, intended for use in a solar cell power supply setup where a quick ‘too low’ or ‘just right’ voltage indicator is needed. The circuit consists only of one 5V regulator, two transistors, two LEDs, five resistors, two capacitors, and one small battery. Although a 4-V battery is indicated, 4.5 V (3 alkalines in series) or 3.6 V (3 NiCd cells in series) will also work. The specifications of voltage regulator IC1 are mainly determined by the size and number of the solar cells and the current pull of the equipment connected to the output. Here the low-drop 4805 is suggested but other regulators may work equally well as long as you observe the output voltage of the solar cells. Transistors T1 and T2 are complementary types i.e. one each of the pnp and npn variety. Circuit diagram:  Although the ubiquitous BC557B (pnp) and BC547B (npn) are indicated, any small-signal equivalents out of the junk box will prob...

High efficiency white LEDs have advanced to the point where they can replace glow bulbs and other light sources not only as indicators, but also for illumination. While many of the claims made about the LEDs' efficiency, light quality, lifetime and economy are mostly exaggeration, the truth is that for very low light levels they are now competitive. They have equal or slightly higher efficiency than a flashlight bulb, a longer lifetime, and are very much tougher. On the other hand, they are still far more expensive than a bulb, for a given light output. Single Cell LED Flashlight  Circuit Diagram It follows that LEDs are almost ideal for very tiny, low power flashlights, in the less-than-one-watt category. But such a low power flashlight makes sense only if the whole flashlight is small and lightweight, and has a reasonable battery lifetime. But white LEDs require about 3.3 volts each, and typically some extra voltage is needed to provide room for current regulation! That's why...

Circuit showing a mobile phone jammer . A beautiful diy gsm jammer or mobile cell phone jammer schematic diagram for use only in GSM1900 with frequency from 1930 MHz to 1990 MHz. The GSM1900 mobile phone network is used by USA, Canada and most of the countries in South America. This cell phone jammer is not applicable for use in Europe, Middle East, nor Asia. The GSM jammer circuit could block mobile phone signals which works on GSM1900 band, also called DCS. For more cell phone jammers check the related posts.  Circuit Diagram