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Light Laser LED
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Data Bus Circuits
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RF Converter Circuits
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Video Wall circuits
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8051 / 8052
PCB CAD Software
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555 Timer Circuits
Remote Control Toy
H Bridge Circuit
Interconnection & Timing
Digital Signal Integrity
Digital & Bipolars
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4 Band Resistor
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Meter Counter Circuits
IC Up/Down Counter
The GM Counter Accessory is shown below. It can generate a DC voltage upto 1 KV using the 5V pulse generated on PWG. The duty cycle of the pulse is varied to control the voltage. The high voltage applied to the GM tube is divided by 200 and connected to CH0 for monitoring. The pulse generated by the GM counter when radiation passes through it is p
Clock keeps on ticking
I designed and built this Ring Counter Clock in 1970. The base is a 12" diameter/2" thick block of walnut from a hollowed-out gun stock blank. The back side of the base has been hollowed out to hold the circuit board. I chucked it up in a large lath and turned it inside and out. Then I drilled 120 holes for the lights and five holes in the center
AFX Slot Car Lap Counter
AFX slot car sets are very enjoyable but you can increase the fun with a lap counter. This circuit will count from 00 to 99, with independent counters for each track. The sensing device used is a Hall effect sensor (UGN3503; available from Dick Smith Electronics). One of these sensors is glued under a section of each track (printed side up); betwe
Quick Counter For Young Children
This circuit is a toy to encourage young children to count. Power is turned on by switch S1, then S2 is closed. This makes nine LEDs flash slowly. S2 is then opened and the LEDs go out. Pressing pushbutton PB1 turns on a random number of LEDs - briefly - during which time they are to be counted. The number counted can be checked by pressing PB2 wh
lf253 Frequency counter 1Hz-100Mhz with LCD display and RS232 interface
This article continues the AT90S4433 Microcontroller series. I suggest you to read the previous articles on Atmel Microcontroller programming with regards to: This time we design a frequency counter which can measure frequencies from 1Hz to 100MHz. Alternatively you can use it also to just count events, such as how many people crossed the street (
light gate with counter
The circuit described here counts the number of times that an infrared beam is interrupted. It could be used to count the number of people entering a room, for instance, or how often a ball or another object passes through an opening (handy for playing shuffleboard). The heart of the circuit consists of you guessed it a light gate! Diode D1 is an
Geiger Counter Schematic Help
With the recent events at the Fukushima Dai-ichi nuclear power plant, I thought it would be pretty cool to build a Geiger Counter and hook it up to my NerdKit for interfacing with my computer. I`ve found this article which explains the building process pretty well, and also includes a schematic: Unfortunately, the section that describes the circui
Frequency Counter PIC 16F84
DIY/Homemade Geiger Muller Clicker V1
Because the recent events in Fukushima, Japan, brought a lot of concern on radiation levels, by popular demand, here is a simple Geiger Muller counter using the Russian tube SI-22G and a single transistor regulated inverter that puts out 400V, as required. The complete setup has been assembled in only 5 minutes, so this is a very simple detector,
Coil Winding machine counter with Atmega8 and Reed relay
Using an Atmega8-8PU (configured for 8MHz with external crystal), a Nokia 5110 lcd, and a transistor to handle the pulses from a reed relay. A 3. 3V regulator provides the voltage for the entire circuit. Everything has been mounted on a test board, including the headers for: ISP programmer ( USBAsp ), the 5110 Nokia LCD, the power supply (5V in,...
LM2917 frequency to voltage converter
This circuit uses an LM2917 frequency to voltage converter. The input was connected to the low voltage side of the ignition coil, and the various components around it design to produce a full scale output at 6000rpm, which corresponds to 12000 ignition pulses per minute, or 200Hz. The voltage from this was then fed to 2 cascaded LM3914 bargraph dr
DS-300 Lap Counter with Optical Interface
Beeping Down Counter Circuit
The schematic for this project isn`t too, too bad to look at even though it`s not the best drawing/layout for a schematic that I`ve ever done. The basic flow is from left to right. Left side is the state machine, then the 555 timers, then counter circuitry and finally the 7 segment LED output circuitry. The theory section explained this already a
Build A Digital Tachometer/RPM Counter Circuit
The circuit for the Digital Tachometer/RPM Counter tutorial consists of only a few devices. Wire them up according to the following circuit diagram. The PIC I`m using is on a demonstration board, which means the clock, power and ground pins are already wired up so I didn`t bother to include that on the schematic. This is the digital tachometer po
13 GHz Frequency Counter Prescaler
A fairly simple "divide-by-1000" circuit which was first designed by Zeljko Bozic, S52ZB, in a 2006 issue of VHF Communications Magazine. The idea of this project is to extend the range of older (and cheaper) frequency counters. You can often find 100 MHz frequency counters for as little as $20 at hamfests or eBay, and this simple circuit wi
PIC Frequency Counter with Frequency Lock
This PIC software combines frequency counter and frequency lock functions. By adding couple of transistors and operation amplifier TL082, it is possible to lock the LC oscillator frequency. Frequency reference is formed from the measured frequency itself after the delay defined by parameter 0Dh, when the number of the consecutive samples (defined
BINARY DECIMAL LED DISPLAY VERSIONS OF THE SIMPLE FREQUENCY COUNTER
There are other display methods than the original 8 led frequency counter has. They are perhaps easier to read and may have a format that fits better to the front of your QRP equipment. Here some examples of binary decimal displays are given. Mostly the the counter is made without the MHz position, only the kHz position is used to read the VFO fre
frequency counter PIC-Based Digital
Apply power to the frequency counter and set the coarse (top pot) and fine (bottom pot) adjustments to show zero frequency on the display. Turn the pots counter-clockwise to set to zero. Sometimes the counter will show all squares and no digits. Disconnect and re-apply power and the digits should show. Also, turn the viewing angle of the display
VHF & UHF universal frequency meter
2.5GHz Frequency Counter
Debounced Counter Made From Off-The-Shelf Chips
The real usefulness of the SR latch comes during input switch transitions. Let`s assume the input switch is a break-before-make and the switch starts in the up position. From the prior analysis, the inputs values when the switch is up are low, low, high, high, and the output is high. As the switch is toggled, it breaks the first input, changing it
Charge-sharing symmetric adiabatic logic in countermeasure against power analysis at cell level
Digital counter demonstration circuit
555 timer is used as clock to drive RS7490 decimal timer, BCD output to 7 section LED. To adjust R1 can change the clock frequency..
Frequency counter 400Hz to 50MHz with PIC 16F84
It consists only from Microchip PIC 16F84 cpu and LCD text module. Author states that this counter is capable metering frequencies from 400Hz to 50MHz. I used faster, 20MHz version of 16F84A-20I/P, and it managed to count 80MHz oscillator output.
Binary Synchronous Counter Circuit of 74HC161
The display application circuit diagram of 74LS161 counter
Winding electronic counter 2
The winding machine electronic counter described in the example uses LED digital display to show the wound coil turns, the use of maximum count rate is 9900 turns. The working principle The winding machine circuit is composed of the power circuit, infrared switch circuit, shaping / transformation circuit, reset circuit, divider circuit and the...
12V 5MHz COUNTER
Portable counter is designed with low-power logic to minimize battery drain, yet provides good performance.Since most of milliwatt power drain is taken by digital readout, circuit blanks out LED display when there is no input signal. Time base divides 1-MHz crystal oscillator frequency down to desired enable time, up to tOs, using 31/2 MC14518...
Access room people number counter circuit
Working principle: Two pairs of photoelectric detection devices are installed in the access channel. On one side the light source A (transmitter) and the photoresistor LDR1 (receiver) are installed in the entrance of the channel; on the other side, the light source B (transmitter) and the photoresistor LDR2 (receiver) are installed in the outlet...
Frequency Meter Circuits
VU Meter Circuits
Ultrasonic distance finder circuit
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is measured. There are three main categories of distance measurement methods in use: a) By...
Simple Metal detector circuit with CD4030
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to find something potentially valuable, hidden a few centimeters below the soil. So many...
Fully automatic watering circuit for flower pots
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This circuit comes as a solution to this problem. Depending on humidity of the pot at...
Simple deep searching metal detector circuit
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the circuit of this metal detector, it is possible to detect a metal coin in depth of 90 to...
Sub-Harmonic Bass Converter for Electric Guitars
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound, such as filtering or distortion. Instead, a frequency division system produces outputs...
Echo Depth Sounding Sonar for Boats
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the calibration of the rope. This arrangement still exists in some yachts. The big...
100W HiFi Audio Amplifier Circuit
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power supply must be symmetrical so that no electrolytic capacitors are needed at the outlet....
Plant-Pot Water Level Indicator Circuit
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower. The circuit of the device is shown in Figure 2. The water detection is made from the bottom...
Analogue Sound Preasure dB-Meter Circuit
The best human ear can capture sounds from 20Hz to 20KHz. These limits are known to be the broadest that can exist. Normally the normal limits range from 100Hz to about 13KHz and depend on the age and health of the individual. We for our measurements and to have a good accuracy we will get the limits of 20Hz to 20KHz. A sound to be heard does...
Digital Signal Integrity
Interconnection and Timing of Digital Circuits
CMOS Circuits Tutorial