Meters Circuits
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Simplified logic checker. Logic voltage levels have the ability to display LED (Of course I (^_^;)." H "in the LED is green," L "and red LED lights, and so both the open and goes out . But not only that was put on the ability to detect narrow pulses. In.... -
Photo diode outputs light current that is well proportional to input light power when it is used in short mode. In this lux meter, the output current is converted to voltage with an I-V converter, it is captured by a micrcontroller and displayed it in term.... -
This is a portable oscilloscope adapter that it can be held in breast pocket. Its operation is only sampling and sending to host PC. The most of functions of the oscilloscope are processed by host PC. Therefore, oscilloscope adapter can be simplified. This.... -
This article has two parts. Part I describes a way to determine the effective average impedance of a pair of mono headphones or a speaker using a device called a FILVORA. This is the optimum resistance with which to drive the headphones or speaker to obtain.... -
This simple circuit has helped me out on many occasions. It is able to check transistors, in the circuit, down to 40 ohms across the collector-base or base-emitter junctions. It can also check the output power transistors on amplifier circuits. Circuit.... -
Stick the metal probes into a freshly watered plant and adjust R5 for a mid-scale meter deflection. The meter will monitor the soil wetness and the meter will indicate whether it is to moist or to dry. This circuit uses a dual power supply which could be.... -
When testing circuits with a logic probe, it is sometimes difficult to watch the LEDS on the probe to determine the logic state. With this probe the logic states are audible. This probe is designed for TTL circuits only but could be modified for CMOS. The.... -
The proposed capacitance is a very powerful assembly to measure in 7 ranges capacitors of 1 pF to 999 uF, avecune excellent precision of about 10 -3 . The range change is fully automatic. The display shows 3 digits with decimal point. Three LEDs.... -
Pin 3 defines the Display type: Common Cathode or Common Anode. Connect this pin to GROUND if you are using common cathode 7-segment led displays. To use common anode displays, connect it to VCC (positive) Pin 4 is the signal input, you can use optical.... -
I made this project as a test to improve a technic to read analog values without analog-to-digital converter. (ADC) I ended with this "sound meter". It may not work perfectly, it needs some improvement but works anyway. It have the feature of.... -
Working on live telephone circuits can be a problem. You just can't connect a normal scope probe to the circuit while it is tied to the phone line. Neather side of a phone line is ground. When a phone or other device is 'offhook', one side floats at about.... -
This site contains public-domain schematics for a dual-trace, triggered oscilloscope, and some theory. Click on the topic in the table below to see the schematic for that block. I designed and built this oscilloscope in 1986 using the chassis of a.... -
The circuit below provides the horizontal drive voltage. The supply voltage on one end, +135 to +165, is made variable for the horizontal position control... -
This circuit blanks the CRT starting just before retrace begins. Since the CRT sits at a -1200 volt potential, the blanking circuit must also be based at -1200 volts. Note the capacitors, C40, C41, and C43 which allow the gates that drive the intensity grid.... -
The high voltage section of the CRT is unchanged from the original vacuum tube oscilloscope used as the basis of this design. The CRT requires shielding from the main power transformer. Cold roll steel around the CRT does not provide enough shielding from.... -
The vertical deflection amplifier uses a 180 degree phase splitter to generate a differential signal. The CRT requires large drive voltages, but almost no current. The oscilloscope bandwidth is limited by the amplifier chain as almost all electrostatic CRTs.... -
The analog switch multiplexes between channel 1 and channel 2 at the end of each sweep. Controls include Dual Trace/Single Trace mode, sync polarity, sync level, and sync on + or - (rise or falling) edges... -
The DC-10 MHz amplifier shown below is identical for both scope channels. The input FET should be mounted directly on the adjustable attenuator switch for best frequency response. The vertical position pots, R27 and R51, change the dc level of the traces,.... -
The input attenuator uses a commutating capacitor to cancel the input capacitance of the FET buffer (see DC-10 MHz amp schematic). The commutating capacitors are absolutely necessary to cancel the effect of the input capacitance to the DC-10MHz amplifier..... -
This site contains complete schematics and code for a 68HC11 based frequency counter, square wave synthesizer, sine wave synthesizer, programmable filter, capacitance and inductance meter, with a digitalker speech synthesizer output. Project specifications.... -
This instrument is a one or two channel frequency synthesizer. DC to 35 MHz frequency with 0.1 Hz resolution. +16 to -48 dBm signal level with 0.1 dB resolution. adjustable phase between the 2 channels with 11.25 degree resolution. pushbutton and knob.... -
Many times we have found itself in the necessity to use a Zener diode and cannot to know the voltage of operation. Many times we cannot read the characteristics or the type that is written on her. In this case, but in different we can also use the circuit.... -
The design shown will test PNP and NPN transistors, diodes and SCRs both "in-situ" (equipment of course de-energised) and also by direct connection to a stand-alone component. It is a simple GO/NOGO test which can identify diode and transistor action and.... -
This is a simple servo tester which will comprehensively test the capabilities of almost any modern servo. It has two pushbuttons, CENTRE and SWEEP and a potentiometer which works as follows: - CENTRE Does exactly that, centers the servo, afterwards the.... -
This device was designed to use two generic-patterned, pre-made, pre-drilled circuit boards that are available from Radio Shack, and other places. Parts consist of: two generic pre-etched and pre-drilled PCBs (printed circuit boards), 136 precision 1%,.... -
A simple SWR meter first needs a calibration to Uv = 100 % (forward power). When switching over to Ur (reflected power) the SWR is indicated. This procedure has to be repeated every time a change is made to the transmit power, antenna tuner or frequency etc..... -
After one has built a QRP transmitter, it would be interesting to know the exact amount of output power. Without a power meter the peak to peak voltage Vss is measured at an 50 ohm resistance (dummy load) with the available oscilloscope. Now the power rate.... -
You can build an automatic gain control AGC for the superhet receiver with only a few additional components. The first AGC circuit is more universal. It is suitable for audio amplifiers with dual op amps like TL072, TL082, NE5532 and the broadband amp NE592.... -
The Inter-Power SWR-5 - upper right - "isn't worth a penny". Got it from a mate to use with a beacon, but I burnt it out with only 3.5-4W morse signal on 70cm. Removed the bridge and installed my own pick-up line (suggested by LA8OJ) and now it is fb for.... -
Noise level measured into 75ohm 3.1kHz BW using Siemens D2006 level meter: -80dBU (77.5mV) from zero to 1MHz and drops 3dB on 17MHz. Decrease the first coupling capacitor (68nF) to 10nF to increase the lower limit to 50kHz. The amplifier is copied from.... -
This project uses a four-point resistance measurement process also known as the Kelvin method. This procedure uses a current source to determine the value of an unidentified resistance. A constant current flows through the unknown resistance and the voltage.... -
The circuit is drawn for measurement of acceleration from 1000 mg until + 1000 mg. It can be placed in kantra'n the car and be supplied from the sheath of electric lighter. The circuit includes one indicative LED and a screen LCD. The measurement of....
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.....
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