Diagram Diagosis

Aburst water-supply hose of the washing machine, a bathroom tap that you forgot to close, or a broken aquarium wall may turn your house into a pond. You can avoid this mess by using an electronic water alarm that warns you of the water leakage as soon as possible. The acoustic water alarm circuit presented here takes advantage of the fact that the tap water is always slightly contaminated (or has salts and minerals) and thus conducts electricity to a certain extent.

It is built around IC LMC555 (IC1), which is a CMOS version of the bipolar 555 timer chip. IC1 is followed by a complementary pair of emitter followers (T1 and T2) to drive a standard 8-ohm speaker (LS1). Power is supplied by a compact 9V PP3 battery. Power is applied when power switch S1 is closed. The reset input (pin 4) of IC1 is held low by resistor R1 (2.2-kilo-ohm).

The astable oscillator wired around IC1 is in disabled mode. When probes P1 and P2 become wet, these conduct to reverse the state of IC1’s reset terminal. As a result, the astable multivibrator starts oscillating at a frequency determined by resistor R2 and capacitor C3. The output of IC1 drives the complementary pair of transistors T1 and T2.

Electronic Water Alarm Circuit Diagram

Although this combination causes significant crossover distortion, it doesn’t have any adverse effect on the square-wave audio signal processing. A 10-kilo-ohm potentiometer (VRI) is inserted between output pin 3 of IC1 and the bases of transistors T1 and T2 for volume control. The probes can be made using two suitable copper needles or small pieces of circuit board with the copper surface coated with solder.

Fit these at the lowest point where water will accumulate. After construction, place the alarm circuit well away from the point of possible leakage. Use a pair of thin twisted flexible wires to connect the probes to the circuit. Capacitor C1 connected across IC1 input (pin 4 and GND) keeps the alarm circuit from responding to stray electrostatic fields.

Similarly, twisting the wires together makes the relatively long connection between the probes and the circuit less sensitive to false alarms due to external electromagnetic interference. Finally, if you want to lower the probe sensitivity, reduce the value of grounding resistor R1.

The FMS6363 Low Cost Video Filter (LCVF) provides 6dB gain from input to  output. In addition, the input will be slightly offset to optimize the output driver performance. The FMS6363 provides an internal diode clamp to support AC-coupled input signals. If the input signal does not go below ground, the input clamp will not operate. This allows DAC outputs to directly drive the FMS6363 without and AC coupling capacitor (usually 220 ?F). The offset is held to the minimum required value to decrease the standing DC current into the load.

circuit diagram of burglar alarm using IC timer 555/556 is functioned as an alarm to prevent thief entering your house. The alarm would produce loud sound when a thin wire connecting resistor R1 with IC pin no 4 is broken. Thin fiber is used as the wire. The thinner the wire, the more responsive the alarm. This circuit needs 5-15V power supply, buzzer is used as a speaker. Here is the circuit schematic :

Parts list :

•     Resistor R1 : 10k
•     Resistor R2 : 68k
•     Resistor R3 : 1k
•     Polar capacitor C1 : 1uF/15 B
•     Capacitor C2-C3 : 0.01uF
•     IC Timer : NE555

October 2008, Dells provides a new security technologies which is Electronic Privacy Screen for its next-generation Latitude business notebook flagship model E6400. However, there are still few user who understand the function so far. Here I am explain it again today.
Over the past few years, display manufacturers have been increasingly viewing angle will be as a promotional selling point. If you use at home, of course, the higher the better viewing angle, but in the workplace, coffee shop, airport or other public places, privacy and data security issues become more exposed. Members may have noticed that some of my colleagues has focused laptop privacy screen labeled anti-spy film.
Currently, only Dell Latitude E6400 can support electronic security shield technology, Dells official website users can be customized when ordering. This notebook is equipped with software-driven display screen can create a pixel-based pattern, so it can narrow the viewing angle the screen to avoid being shown the privacy of important data or content is sweeping others. This feature is activated, the user only in the notebook before had just being able to clearly see the displayed content, and in the side, the content is completely unable to see.
Electronic Privacy Screen almost have nothing to do with the display brightness, it can be activated just by the shortcut key combination (FN + E) or the Dell ControlPoint software. The consumers who focus on data security and privacy of may try it.