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

This will flash a LED, employing a single 1.5v cell. it's going to even flash a white LED even supposing this kind of LED needs regarding three.2v to 3.6v for operation. The circuit takes regarding 2mA however produces a really bright flash. LED on 1.5v SUPPLY A red LED needs regarding one.7v before it'll begin to illuminate - below this voltage - NOTHING! This circuit takes regarding 12mA to illuminate a red LED employing a single cell, however the fascinating feature is that the approach the LED is illuminated. The 1u electrolytic may be thought of to be a 1v cell. (If you wish to be technical: it charges to regarding one.5v -0.2v loss as a result of collector-emitter = one.3v and a lost of about 0.2v via collector-emitter in diagram B.) It is firstly charged by the 100R resistor and therefore the third transistor (when it's totally turned ON via the 1k base resistor). this is often shown in diagram "A." throughout this time the second transistor isn't turne...

1.5V POWERED LED FLASHER ELECTRONIC DIAGRAM It is a charge pump design. This is where a capacitor (electrolytic) is allowed to charge and is then raised higher and allowed to discharge into a load. The load sees a voltage that can be higher than the supply.

The basic 2 LED astable multivibrator flasher built by Mary. She chose to use 2 different colored LEDs and the red LED is clear when unlit. It is quite bright when lit compared to the yellow LED despite the fact that it only draws 0.5 mA more. The bread boarded test circuit was powered by a new 9 volt battery and was regulated by a L78L05 (in a TO-92 package as shown in the schematic). The 5 volt regulator was used to avoid exceeding the reverse breakdown voltage of the 2N3904. This topic will be discussed a little later on. 470 ohm current dropping resistors were chosen to keep the collector current draw less than 10 mA. The LEDS were bright enough to see well in dim lighting. You may change this resistor "R" value (lower R = brighter), but do not exceed the maximum current rating for the LED or transistor (this is more applicable to higher voltage multivibrators). You may also place 2 or more LEDs in series on each half of a multivibrator, however, the current dropping...

This is a unique flasher circuit employing a single driver transistor that takes its flash-rate from a flashing LED. The flasher within the photo is 3mm. An ordinary LED won't work. The flash rate can not be altered by the brightness of the high-bright white LED will be adjusted by altering the 1k resistor across the 100u electrolytic to 4k7 or 10k. The 1k resistor discharges the 100u in order that when the transistor activates, the charging current into the 100u illuminates the white LED. If a 10k discharge resistor is used, the 100u isn't absolutely discharged and therefore the LED doesn't flash as bright. All the components within the photo are within the same places as within the circuit diagram to make it simple to envision how the components are connected. The circuit uses a flashing LED to flash a super-bright 20,000mcd white LED