Checker Circuits
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For those of us who don t like to get their hands dirty, this simple soil moisture tester quickly checks the state of their plants and how much attention t.... -
Do not let its extreme simplicity deceive you — this thing is useful! I have made many over the years and have even given some away as gifts. Yes multimete.... -
Servo refers to an error sensing feedback control which is used to correct the performance of a system. Servo motor is a DC motor equipped with a servo mec.... -
The idea for this crystal tester circuit sprung out of the need of testing a large number of oscillator crystals lying unused in a big hobby box. testing the crystals one by one without the appropriate device would have been very slow and a time consuming.... -
T1 and XTal have formed an oscillator. C1 and C2 are voltage divider for oscillator. if the XTal is safe, the oscillator will work well and its output voltage will be rectified by C3, C4, D1 and D2, then T2 will run and LED will light. The circuit is.... -
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.... -
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. Electronics project.... -
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.... -
This small circuit is ideal for checking the basic operation of an infrared remote control unit. The circuit is based on the brilliantly simple idea of connecting a piezo buzzer directly to an IR receiver IC. This method is almost as simple as connecting a.... -
A very simple device allowing a quick check of common Infra-red Remote-Controls can be useful to the electronics amateur, frequently asked to repair or test these ubiquitous devices. A reliable circuit was designed with a handful of components: the LED will.... -
Here is a simple tester for checking the basic operations of an infrared remote control unit. It is low-cost and easy to construct. The tester is built around infrared receiver module TSOP1738. Operation of the remote control is acknowledged by a tone from.... -
Is the battery empty, or is there something wrong with the device That`s always a difficult question when your walkman or some other battery-powered device appears to be dead when you switch it on. Before you take it to the shop for servicing, the first.... -
This simple circuit tests speakers, microphones, transformers and voltage. It`s basically a very low frequency oscillator that produces extremely short `fruity` pulses. The type of sound produced is very easy to hear and to determine the precise direction it.... -
This simple circuit uses a 741 op-amp in differential mode as a continuity tester. The voltage difference between the non-inverting and inverting inputs is amplified by the full open loop gain of the op-amp. Ignore the 470k and the 10k control for the.... -
Using a single 555 Timer IC and a small transformer to generate a high voltage, this circuit will test zener diodes of voltage ratings up to 50VDC. The 555 timer is used in the astable mode, the output at pin3 drives a small audio transformer such as the.... -
To build astepper motor tester, the circuit contains two sets of drivers that can support both unipolar and bipolar stepper motors. The control circuit and driver circuit are in separate power supplies that can work on a wider rangeof different power.... -
Here is a small device for HAM amateurs, how using powerpole connectors to connect ham gear to unknown power supply with powerpole connector. But you.... -
I assume anyone who wants to make this can read the schematics bellow Basic principles:NOTE:Li-Ion batteries shouldn`t be discharged bellow 3V (In.... -
As MIDI data is transmitted between instruments using a current loop, a opto-isolator (6N139) is used to convert this current loop into TTL pulses. Th.... -
The meter has only one scale (0. 150) but this also used for 0. 75 and 0. 30. This is such a pain, and all people use a calculator with it. I made a new meter scale for it, with all ranges. This improves the comfort so much New Meter Scale for your L3-3! Due.... -
A simple Zenner diode tester circuit, when coupled with a PWM generator it can be used to measure the breakdown voltage of Zener diodes. Or more generically, it can be used to measure the breakdown voltages (e. g. BVceo, BVcbo) of BTJ transistors. As you can.... -
The design is based loosely on some ideas from K8CU and AG6K. However, I have simplified the circuit somewhat and used different components. The mechanical encapsulation is also different. I used LTspice to verify the tester before building it. The schematic.... -
This design will interest technicians who work on pneumatically operated valves and other 4-20mA current loop controlled devices. Although 4-20mA signal injector/calibrators are available, this one is both cheap to build and easy to operate. When first.... -
Is the battery empty, or is there something wrong with the device That`s always a difficult question when your walkman or some other battery-powered device appears to be dead when you switch it on. Before you take it to the shop for servicing, the first....
New Circuits
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This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of.... -
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.... -
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.... -
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.... -
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.... -
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,.... -
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.... -
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.... -
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.....
Popular Circuits
As you see in the circuit above the four pins "Controller pin 1", 2, 3 and 4 will control the...
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A circuit that uses one cycle in an alternating current to produce direct current. A Half-Wave...
What do you do with those old 2-Meter FM rigs that don`t have any CTCSS tone capability Well, you...