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8051 / 8052
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Meter Counter Circuits
Self-Powered Fast Battery Tester Schematic
FET Q1 provides a constant current generator biasing LED D1 and Q2 Base. In this manner D1 illuminates at a constant intensity, independent of battery voltage from 3 to 15V and Q2 (when P1 is closed) applies a constant current load of about 120mA to the battery. IC1 is a square wave generator oscillating at about 3KHz. IC2 acts as an inverter and
Simple Cat.5 Network Tester
This circuit came from a need for a "quick and dirty" network tester that could be operated by one person. All the commercial units I tried required a person at the other end to check the remote LEDs, as the transmitters could not be made to cycle through the test continuously to allow one person to check both ends. It must be noted that this unit
simple but reliable car battery tester
This circuit uses the popular and easy to find LM3914 IC. This IC is very simple to drive, needs no voltage regulators (it has a built in voltage regulator) and can be powered from almost every source. When the test button is pressed, the Car battery voltage is feed into a high impedance voltage divider. His purpose is to divide 12V to 1, 25V (or l
network wiring tester schematic circuit
This network wiring tester comprises two elements, a transmitter unit, powered and fitted at the network start point, and a receiver unit, passive, which can be moved around from socket to socket. Each of these units carries eight LEDS, identically labelled 1 to 8. By operating a push-button in manual mode, or using a clock in automatic, the...
simple cable tester
SIMPLE CONTINUITY TESTER CIRCUIT
This circuit have an advantage over ordinary CONTINUITY testing Device, usually we are using multimeter to check the continuity of a circuit. It is not suitable to check the continuity of a circuit with high Impedence or resistance like Transformer, Capacitors, and even for high value Resistors. This circuit helps you to determine whether the devi
US-Army I-177-B Mutual Conductance Vacuum Tube Tester
PIC Stepper Motor Tester
Determining which drive wire is which on a unipolar stepper motor. This is the type of motor that I have most commonly found surplus or in salvage equipment Platform: PIC16F877A using BoostC connected via rs232 to a PC running a terminal program. The PIC chip is supplemented with a MAX232 chip and a ULN2003 driver. I have used a PIC 16F877A for...
The RF Tester (A3014) is a combination of four circuits. Its purpose is to test several circuit ideas, both by implementing them, and by providing better support circuits for their development. The Modulating Transmitter (A3014MT) replaces our original Modulating Transmitter ( A3001A ). The A3014MT allows you to set the DC voltage applied to a MAX
Video Head Tester
Quick on-board Junction Tester
Constant Current LED Tester
Most of my circuits still use 5 V regulated power for the chips, because 8-bit microcontrollers run faster and some sensors require 5 V. Since 5 V is more than enough for even a white LED, I`m not concerned with the voltage needed by a particular LED in use. However, since my robots are battery powered, I am concerned with the current usage,...
UTP cabel tester
The UTP Cable Tester can be used for many purposes. Mainly to test a UTP network cables of course. However it can also be used to find the right cable in a large bundle of identical looking cables. In fact the circuit can be used or adapted to test any type of cable of any number of wires, provided that the tester is equipped with the...
The circuit is based on the grid-dip or absorption effect, which occurs when a parallel resonant circuit is coupled to an oscillator of the same frequency. Q1 operates in a conventional Colpitts oscillator circuit at a ftxed frequency of approximately 4 MHz. A meter connected in series with the transistor`s base-bias resistor serves as the dip...
DC capacitor tester circuit diagram composed of 555
DC capacitor tester circuit diagram composed of 555 is shown as the chart. The tester is composed of the pulse generator, one-shot, DC amplifier and meter indication circuit. It can measures the npF ~ 10?F capacitor. The range is divided into 0 ~ 100PF, 0 ~ 1nF, 0 ~ 10nF, 0 ~ 100nF, 0 ~ 1?F, 0 ~ 10?F..
Quartz crystal tester is needed if you want to know whether the crystal is good or bad (broken). This crystal tester gives LED light indicator. If the..
Audible Transistor Tester
All types of transistors including Darlington and power will be tested in this project. Connect the 9v battery around the other way at points A and B to test..
Continuity And Component Tester
This continuity tester gives a beep sound if detect an electric current conduction between its probes. Here is the schematic diagram of this audible..
Good/Bad Transistor Tester
Good/Bad transistor tester means that this instrument can only determine if the transistor is good or bad, nothing more. Any transistor with gain equal to 30..
Simple IR Remote Tester
Most cases of infra-red remote control failure can be detected by detecting the absence of the pulsed transmitted infra red light. It`s very rare that the..
JFET Pierce oscillator will test any crystal from 50 kHz through 25-MHz upper frequency limit of fundamental-mode crystals without tuning, and drive counter for measuring crystal frequency, Will test overtone VHF crystals on their fundamental frequency. T1 is small output transformer from tube-type radio, having about 33: 1 turns ratio, or 6. 3-V f
I needed to test some crystals for a project I was working on. I found lots of testers on the internet, but they all where lacking in one thing or another. I decided to take one of them and add the features that I wanted to it. This is the result. I also designed a small circuit board for it.
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