Rongge

Hello Freinds ! Here designed SIMPLE BAR DISPLAY WITH ALARM FLASHER . Schematic: Return to Display Circuits. By using two switching transistors and two LEDs, this circuit can distinguish low-level ac and dc signals. If the red LED illuminates, the signal is positive dc. If the yellow LED lights, the signal is negative dc. If the signal is ac, both LEDs will light. Bar Display With Alarm Flasher Circuit Schematic

The whole project was developed on a friend's request. Its purpose was to remotely monitor the water-level in a metal tank located in the attic by means of a very simple control unit placed in the kitchen, some floors below. Mains requirements were: No separate supply for the remote circuit Main and remote units connected by a thin two-wire cable Simple LED display for the main unit Battery operation to avoid problems related to mains supply and water proximity As the circuit was battery operated a low current consumption was obviously welcomed The very small remote unit is placed near the tank and measures the water level in three ranges by means of two steel rods. Each range will cover one third of the tank capacity: Almost empty - signaled by means of a red LED (D3) in the control unit display About half-level - signaled by means of a yellow LED (D2) in the control unit display Almost full - signaled by means of a green LED (D1) in the control unit display Simple Water Level...

Using the LMD18200 3A H-Bridge designed by National Semiconductors for motion control applications can be designed a very simple motor controller electronic project . Ideal for driving DC and stepper motors; the LMD18200 accommodates peak output currents up to 6A. An innovative circuit which facilitates low-loss sensing of the output current has been implemented. LMD18200 Motor Controller Schematic This circuit controls the current through the motor by applying an average voltage equal to zero to the motor terminals for a fixed period of time, whenever the current through the motor exceeds the commanded current. This action causes the motor current to vary slightly about an externally controlled average level. The duration of the Off-period is adjusted by the resistor and capacitor combination of the LM555. Using this motor driver circuit you can design a 24 DC motor that require a maximum current consumption of 3 amperes .

Desktop computer power supply - ATX type Delta Circuit diagram Click on the schematic to magnify

This circuit is sensitive to low frequency electromagnetic radiation and will detect for example hidden wiring or the field that encompasses a transformer. Pickup is by a radial type inductor, used as a probe which responds well to low frequency changing magnetic and electric fields. Ordinary headphones are used to for detection. The field that surrounds a transformer is heard as a 50 or 60Hz buzz. The circuit is below:- Electromagnetic Field Detector Circuit Diagram Notes: I threaded a length of screened cable through an old pen tube and soldered the ends to a radial type can inductor. I used 1mH. The inductor fitted snugly into the pen tube. The opposite end of the cable connects to the input of the op-amp. Any op-amp should work here, possibly better results may be achieved with a low noise FET type such as the LF351. The 2M2 potentiometer acts as a gain control and the output is a pair of headphones. Stereo types can be used if they are wired as mono. I used an 8 ohm type, but the ...

This is a schematic of a simple metal detector that uses technology CCO , by Coil Coupled Operation . Thomas Scarborough designed this new incarnation of the metal detector , a new genre that he invented in 2004 . This is the first project of the Internet and can be built easily.      Metal Detectors CCO Schematic Diagram

We usually lock our luggage utilizing a chain-and-lock arrangement when in travelling by a train of bus. But, still we are worried, apprehending that someone may possibly break the chain and steal our luggage. The following schematic is really a very simple and easy build luggage security alarm circuit to alert you when a person tries to break the chain. Transistor T1 allows supply to the sound generator chip when the base current begins flowing through it. When the wire (thin enameled copper wire of 30 to 40 SWG, applied for winding transformers) loop around the chain is cracked by someone, the base of transistor T1, which was previously linked with positive rail, becomes opened. Because of this, transistor T1 gets forward biased to extend the positive power source towards the alarm circuit.   In idle mode, the power source consumption within the circuit is lowest and as a result, it could possibly be utilized for numerous travel hrs. To make it possible for generation of various ...

Sony Trinitron KV20TS50 - Circuit Diagram SMPS Main board Click on the schematics to zoom in