Readout Circuits
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Light onphototransistorQ1 (Radio Shack 276-130) produces voltage change across R2 for amplification by opamp whose output drives array fiveLEDs forming bar graph voltage indicator. Adjust R3 initially for highest sensitivity by tuming off room lights and.... -
The analog display consists of a frequency/voltage converter (IC12) and bar-graph segment drivers IC10 and IC11. R34 is the calibration adjustment and is set so that an engine rpm of 5000 to 7000 rpm lights the first LED (redline value). .. -
Uses only six components per stage. Combining of counter and indicator functions gives low battery drain. After reset button is re leased, 0. 22-mid capacitor insures that first stage turns on. Current is drown by stage only when lamp is on. Any number of.... -
Sections of RS339 quad comparator each drive LED to give indications of four different input voltage levels, While LED 1 is connected to ground for use as zero indicator Resistors shown are for Radio Shack 276-041 red LEDs ›change R6-R9 to 270 ohms and R1 to....
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.....
Many times we have found itself in the necessity to use a Zener diode and cannot to know the...
This simple diode modulator delivers excellent results when used for high percentage modulation...
The gate drive that phase controls the four parallel SCRs is accomplished with complementary MOS...
Probe/contacts may use a non-reactive metal. Gold or silver plated contacts from an old relay May...
A harp without strings i. e. IR sensor-receiver pairs function as strings in our device. The...
This is the circuit diagram of a very sensitive electromagnetic field sensor which can sense...
Here is a simple technique for measuring frequencies over quite a wide frequency range and with...
The last section presented a number of basic free-air laser light communications projects. You...
The National Semiconductor LMV225 is a linear RF power meter IC in an SMD package. It can be used...
Circuit works: Rp1 ~ Rp13 scale resistance to the keyboard, but also the oscillator timing...
Timing IC using long RS6445C constitute blocking oscillator As shown in the timing for the...