Category : " Display related circuits "
Subcategories
Low-battery indicator with LED flasher
Catagory : Indicator
Typical low-battery indicators simply turn on an LED when the battery voltage drops below a certain value. Such circuits actually accelerate the battery’s extinction by drawing excessive current. This circuit draws a mere 1 mA in its standby mode and averages only 20 m A when activated. The low current imposes a minimal burden on any battery circuit.
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Propeller Clock : A Mechanically scanned digital clock
Catagory : Clock circuits, PIC microcontroller
The PIC16F84 that is used is a very basic& cheap FLASH µController from MICROCHIP.
It has 13 digital I/O’s of which just 5 are used here. The PIC16F84 has no analog inputs or outputs.The controller is ideal for experimenting because it can be erased and re-programmed 1000 times.For easy time calculation the circuit used a 10.24 MHz Xtal.
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Analog Bar Graph Expanded Scale Voltmeter
Catagory : LED Bargraph, Volt Meter
The circuit acts like a magnifying glass on part of the scale of an ordinary meter, namely the part of the scale we are interested in. For example, an ESV for testing a single NiCd cell would range from 1.17V at one end of the scale to 1.28V at the other end of the scale. With the full scale covering this narrow range, it’s easy to see voltage changes within the range.The circuit described here uses a bar graph display consisting of eight LEDs.
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An LED Bargraph Optical Tachometer
Catagory : Acceleration Meter, LED Bargraph
Each LED in the bargraph indicates an interval of this size. In practice (and with practice), the resolution is higher. When an RPM reading is taken that falls between two of the LEDs, both LEDs will flicker, and you can interpolate between the two values by the relative amount of time that each LED is on.
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Broken Charger-connection Alert
Catagory : Indicator, Other test circuits
The circuit is inserted between the supply and the load, therefore, until a trickle-charging current of at least 100µA is flowing towards the load, D1 and D2 will conduct. The forward voltage drop (about 1V) available across the Diodes, drives Q2 into conduction and, consequently, Q1 will be cut-off.If no appreciable load is connected across the circuit’s output, Q2 will become cut-off, Q1 will conduct and the Piezo-sounder will beep.
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What Circuits ?
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- Alarm and Security
- Audio / Signal Processing
- Audio circuits
- Automotive
- Battery charger circuits
- Communication
- Computer related circuits
- Controller
- Display related circuits
- Electronic switch circuits
- Encoder and Decoder
- Fun circuits
- How to and Ideas
- Input/Output circuits
- Instruments Circuits
- Laser related circuits
- LED circuits
- Light control circuits
- Microcontroller
- Motor control circuits
- Power supply circuits
- Remote control circuits
- RF circuits
- Sensor circuits
- Signal generator circuits
- Software
- Sound and Music circuits
- Telephone circuits
- Temperature related circuits
- Timer/Counter circuits
- Uncategorized
- Video circuits
