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The unit has a separate amplifier and oscillator section allowing them to be used separately if need be. The injector is a multivibrator running at 1 kHz, with R5 andR6 dividing down the output to a suitable level (Â«1V). The tracer is a single-stage amplifier that drives the high impedance earpiece
Cmos logic probe
The logic probe can indicate four input states, as follows: floating inputâ€”all LEDs off
100K megohm DC probe
A 741 op amp is used with 100% ac and dc feedback to provide a typical input impedance of 1011 ohm and unity gain. To avoid hum and rf pickup the input leads should be kept as short as possible and the circuit should be mounted in a small grounded case. Output leads may be long since the output impedance of the circuit is a fraction of an ohm
Transistors Q1 and Q2 form a buffer, providing the probe with a reasonable input impedance. Q3 and Q4 form a level detecting circuit. As the voltage across the base-emitter junction of the Q3 rises above 0,6 V the transistor turns on thus turning on Q4 and lighting the red (high) LED. Q5 and Q6 perform the same function but for the green (low)...
Logic test probe with memory
There are two switches: a memory disable switch and a pulse polarity switch. Memory disable is a push-button that resets the memory to the low state when depressed. Pulse polarity is a toggle switch that selects whether the probe responds to a high-level or pulse (+5 V) or a low-level or pulse (ground)
The probe indicates a high or low at 70% and 30% of V+ (5 to 12 V). One section of the voltage comparator (LM393) senses V in over 70% of supply and the second section senses V in under 30%. These two sections direct-drive the appropriate LEDs. The pulse detector is a CMOS oneshot (MC14538) triggered on the rising edge of the LM393 outputs...
Audio-rf signal tracer probe
This economical signal tracer is useful for servicing and alignment work in receivers and low power transmitters. When switched to RF, the modulation on any signal is detected by the diode and amplified by the FET
Ttl logic tester
Gates Gl and G2 together with resistors Rl and R2 form a simple voltage monitor that has a trip point of 1 volts. Gate G3 is simply an inverter. The display section of the tester consists of a common anode alphanumeric LED and current-limiting resistors
The CMOS comparator in the successive-approximation system determines each bit by examining tbe charge on a series of binary-weighted capacitors. In tbe first phase of tbe conversion process, the analog input is sampled by closing switch SC and all ST switches, and by simultaneously charging all tbe capacitors to tbe input voltage. In tbe...
The analog input is fed into the span resistor of a DAC. The analog input voltage range is selectable in the same way as the output voltage range of the DAC. The net current flow through the ladder termination resistance; i.e., 2 KO for HI-562A; produces an error voltage at the DAC output. This error voltage is compared with 1/z LSB by a...
Conversion speed of this design is the sum of the delay through the comparator and the decoding gates. Reference voltages for each bit are developed from a precision resistor ladder network. Values of R and 2R are chosen so that the threshold is 1/z of the least significant bit. This assures maximum accuracy of Â±112 bit.
An aid conversion technique which combines some of the speed advantages of flash conversion with the circuitry savings of successive approximation is termed half-flash. In an 8-bit, half-flash converter, two 4-bit flash aid sections are combined. The upper flash aid compares the input signal to the reference and generates the upper 4 data...
Display interface uses the ICM7218A/B with an 8048 family microcontroller. The 8-bit data bus (DBO/ DB7-IDO/ID7) transfers control and data information to the 7218 display interface on successive WRITE pulses. The mode input pins on the microcontroller. When mode is high, a control word is transferred; when mode is low, data is transferred....
The baseband-audio input comes from the pole of switch Sl in the stereo decoder, and is coupled to IC1 (a CA3089) via a 78.6 kHz bandpass filter that consists of capacitors Cl and C2, and inductor Ll. IC1 is a combination i-f amplifier and quadrature detector normally used for FM radio systems operating within an i-f of 10.7 MHz. The device...
Adding a pair of one shots to the output of a 567 tone decoder renders it less sensitive to out-of-band signals and noise. Without the one shots, the 56Tis prone to spurious output chatter. Other protection schemes, such as feeding back outputs or using an input filter, do not work as well as the one shots. The output of the 567 is high in...
The transducer circuit can be operated as either a tone encoder or decoder by changing the position of Sl. The operating frequency of that dual-purpose circuit is determined by C3 and R2. Capacitors Cl and C2 are not critical and can be of almost any value between 1 and 5 mf. When the circuit is receiving an on-frequency signal, LEDl...
This circuit, which was developed to monitor the traffic of bumblebees in and out of the hive, differentiates a-to-b motion from b-to-b motion. When used with an optical decoder, the circuit distinguishes clockwise from counterclockwise rotation and provides a resolution of one output pulse per quadrature cycle. Q1 and Q2 are mounted so that...
The piezo transducer operates as a sound-pickup device as well as a frequency-selective filter. By controlling the gain of the op amps, the oscillator can be transformed into a sensitive and frequency-selective tone-decoder circuit. With the gain of U1a set just below the point of self oscillation, the transducer becomes sensitive to...
The following applications circuits are intended to illustrate the following points: A 2-KO resistor should be in series with V + to limit supply current with negative ringing oi the bit. inputs. Temperature compensation for Rns(on) can be provided in the feedback path of the op amp.
The front end of the DAC is configured differentially using dual eight-input IC multiplexer 1H6216 and three LM156 op amps. Following the differential amplifier is the programmable gain stage discussed earlier, with a low-pass filter on the output feeding the IH5110 sample and hold amplifier. The output of the IH5110 is connected to the...
Three CD4007 A IC packages perform the switch function using a 10-V logic level. A single 15-V supply provides a positive bus for the follower amplifier and feeds the CA3085 voltage regulator. The scale adjust function is provided by the regulator output control, which is set to a nominal10 V in this system. The line-voltage regulation...
Where N is the binary number from 0 to 15 formed by the digital input. If the analog input is a fixed de reference, the circuit is a conventional 4-bit D to ac signal, in which case the output is the product of the analog signal and the digital signal. The circuit on the left is a programmable attenuator with weights of 0, 1/4, 1/2, or 3/4....
This peak detector uses a CA3100 BiMOS op amp as a wide-band noninverting amplifier to provide essentially constant gain for a wide range of input frequencies. The IN914 clips the negative half of VfN (R4)/(R3) (R5).
This matrix can show the values of two variables, for example, frequency and voltage. The display is a graph made from a matrix of LEDs. The LEDs on each axis are color coded, red for out of tolerance and green for in, fanning a red band around the inner green rectangle. The two input voltages proportional to the functions being measured are...
The low Rds and high peak current capability ofthe DG419 makes it ideal for discharging anÂ·integrator capacitor. A high logic input pulse disconnects the integrator from the analog input and discharges the capacitor.
When a large number of channels are multiplexed, the outputs of two or more multiplexers can be connected together and each multiplexer sequentially enabled. In the inhibit mode. the multiplexer draws less power and its output and inputs act as open circuits. Theoretically, an infinite number of channels can be accommodated in this way; in...
This circuit reconstructs and separates analog signals which have been time-division multiplexed. The conventional method, shown on the left, has several restrictions, particularly when a short dwell time and a long, accurate hold time is required. The capacitors must charge from a low-impedance source through the resistance and...
This circuit shows a typical multiplex system intended to carry one of 8 inputs into a remote location. A 5-V pulse train is sent down a separate channel to perform timing and synchronizing functions. A 15-V reset pulse is superimposed on the 5-V clock, which is detected by the MM74COO in the receiver.
The probe relies on the power supply of the CUT (circuit-under-test). The input to the probe, at probe tip, is fed along two paths. One path flows to the clock inputs of U2a and U2b. The other path feeds both the inverting input of Ulc, which is set up as an inverting-mode integrator, and the noninverting input of Ulb, which is configured as...
The pulser generates pulses at a user-selected frequency of 0.5 or 500 Hz, with a pulse width of about 5 ms. If the input to be pulsed is already being driven high or low by another output, the pulser automatically pulses the input to the opposite logic state.
An IBM PC can operate the two 12-bit A/D converters in Fig. 1 via its printer port. The converters" serial outputs use only two o
Digital Levels Scope Displays 2 Logic Signals On 1 Scope
Using this simple resistor circuit, you can trick your oscilloscope into displayin
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...
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