Checker Circuits
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Timer Ul operates as a free-running oscillator at 60 Hz, providing trigger pulses to timer U2 which operates in the monostable mode. Resistor Rl is fixed and capacitor Cx is the capacitor being measured. While the output of U2 is 60 Hz, the duty cycle.... -
The calibrator operates on exactly 100 kHz providing a reference for calibrating the variable time base oscillator of general purpose scopes. For example, if the scope is set so that one cycle of the signal fills exactly 10 graticule divisions then each.... -
The 650 MHz Prescaler Probe's input is terminated by resistor Rl and is fed through Cl to the diode limiter composed ofD1 through D4. Those diodes are forward-biased by the +5 volt supply for small-input signals and, in turn, feed the signal to Ul. However,.... -
A single connection change permits division by any integer between 2 and 10. The RCA CD4017A Johnson decade counter is shown connected as a divide by 7 counter. The resistor is used to hold the reset line low. When the appropriate number is reached, that.... -
To buffer a test generator to the outside world requires an amplifier with sufficient bandwidth and power handling capability. The circuit is a very simple unity gain buffer. It has a fairly high input impedance, a 50 ohm output impedance, a wide bandwidth,.... -
The circuit employs a 100 ohm isolation resistor which enables the amplifier to drive capacitive loads exceeding 500 pF; the resistor effectively isolates the high frequency feedback from the load and stabilizes the circuit.. -
With a constant current excitation, the voltage dropped across an inductance in-(in creases with frequency. Thus, an active device whose output increases with frequency can be characterized as an inductance. The circuit yields such a response with the.... -
The monolithic quad operational amplifier provides an inexpensive way to increase display capability of a standard oscilloscope. Binary inputs drive the IC op amp; a dual flip-flop divides the scope"s gate output to obtain channel selection signals. All.... -
The basis ofthe beam splitter is a 555 timer connected as an astable multivibrator. Signals at the two inputs are alternately displayed on the oscilloscope with a clear separation between them.. -
Simple, portable phase-sequence indicator determines the proper phase rotation in polyphase circuits. Major components are two neon lamps, two resistors, and a capacitor. In operation, the leg voltages are unbalanced, so that the lamp with the maximum.... -
This tester provides an audible indication of the logic level of the signal presented to its input. A logic high is indicated by a high tone, a logic low is indicated by a low tone, and oscillation is indicated by an alternating tone. The input is high.... -
The DUT"s(Device Under Test) cathode, anode, and gate are connected to the unit"s K, A, and G terminals, respectively. Pressing switch ·Sl feeds a gate current to the D UT, which triggers it on. Resistor Rl limits the gate current to the appropriate.... -
The pitch of the tone is dependent upon the resistance under test. The tester will respond to resistances of hundreds of kilohms, yet it is possible to distinguish differences of just tens of ohms in low-resistance circuits. Q1 and Q2 form a.... -
Using inexpensive components, you can fit a simple probe circuit into a pencil-sized enclosure. When both LEDs are on, the probe indicates the presence of an ac voltage; either LED alone indicates the presence and polarity of a de voltage. The.... -
This FET probe has an input impedance of 10 M!J shunted by 8 pF. Eliminating the protective diodes reduces this impedance to about 4 pF. The frequency response of the probe extends from de to 20 MHz ( -1 dB), although higher frequency operation is possible.... -
This compact tester checks cables for open-circuit or short-circuit conditions. A differential transistor pair at one end of each cable line remains balanced as long as the same clock pulse generated by timer IC appears at both ends of the line. .. -
A designer often needs to know the value of the internal resistance of a battery. Quite a few testers gi.. -
The battery low-voltage detector uses a CD4093 Schmitt trigger and a capacitor that acts as a 1-bit dynamic RAM. The c.. -
This circuit allows a microprocessor system to measure its own battery voltage. A Texas Instrument TI43.. -
This battery tester makes use of an LM3914 bar-graph driver IC. SI selects load on battery under test and programs the volta.. -
This Nicad battery tester discharges the test battery at a rate of 500 mA. When the endpoint of 1 V (determined by set.. -
The sensing circuit consists of a 741 op amp set up as a voltage comparator, using a zener diode as a voltage referen.. -
Three-terminal regulator device (LM78LXX) has Vout = Vm until the input rises 1.5 to 2 V above the output when the .. -
This unit uses switches and resistors to provide a number of current ranges. It allows you to test most of the meters availabl.. -
A 555 timer drives Ql through Q4 with a square wave. LED1 and LED2 light when an npn or pnp transistor respectively, are .. -
Ul is an op amp used as a comparator. When the test probes are shorted together, resistors R1 and R2 bias the noninverti.. -
This circuit can be used to check up to an eight-conductor cable. IC1, a 555 timer, drives decade counter.. -
The circuit consists of a 5-V regulator, constant-current source Dl, D2, and Ql, and op amp gain stage Ul. Power is provid.. -
A high-gain amplifier using a UA741 is used to sense relative voltage drop in a conductor, and therefore current i.. -
This circuit uses a dc amplifier (324) in a bar-graph circuit that uses an LM339 Quad comparator IC to sense dc levels. .. -
An LF356 op amp is used as a gain amplifier with the output taken across R5, When a full-scale current of 1 mA is flowing.. -
This amplifier can transfer dc-to 5-MHz signals across a potential difference of 25 000 V. This circu..
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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