An NE602 acts as a heterodyne detector and Ql as a sense oscillator. When Ll is brought near metal, it causes a charge in lo..
The search coil, CI and C2 form a tuned circuit for the oscillator which is tuned near the center of the broadcast band. Tune a portable radio to a station near the middle of the band, then tune C2 until a squeal is heard as the two signals mix to produce a beat (heterodyne) note. Metal near the search coil will detune the circuit slightly, changing the pitch of the squeal...
The metal locator uses a one-transistor oscillator and an AM radio to detect metal. Transistor Q1 is a pnp transistor that is connected to an oscillator. Resistor R1 provides the correct base bias and capacitors C3 and 04 and the search coil determine the frequency of oscillation. Capacitors C3 and 04 are fixed in value, but the search coil is an inductor that varies in inductance (and thus varies the oscillator frequency) as metal is brought near it. The oscillator.....
In this project, a wireless communication system is designed and developed for remote patient monitoring. The primary function of this system is to monitor the temperature of a patient’s body, and display the same to the doctor through RF communication. In hospitals, where patient’s body temperature needs to be constantly monitored, is usually done by a doctor or other paramedical staff by constantly observing the temperature and maintaining a record of it. It is.....
Using an oscillator running at 455 kHz, the metal-detector circuit produces an indication on the meter Ml. When the oscillat..
This circuit uses a 15-kHz oscillator coil. When metal placed in the energy field is withdrawn, the oscillator voltage is rectified and compared to a reference...
This circuit uses a 15-kHz oscillator coil. Whan metal placed ixi the energy field is withdrawn, the oscillator voltage is rectified and compared to a reference. A drop in oscillator voltage therefore operates comparator IC2 and D4 (LED) extinguishes. ..
The circuit consists of two oscillators, both working at about 465 kHz. One uses an if transformer and the other uses an inductor (the search coil LI). The oscillators are coupled by a capacitor (10 pF). A beat note (produced if the two oscillators are working closely together) is detected by the diode and fed to the headphone amplifier and the 22 ?F capacitor. The search coil oscillator is tuned by a 10-365 pf variable capacitor. The search coil comprises 22 turns of wire.....
This circuit is on oscillator with LI being a 4" diameter coil of 35 turns of #26 magnet wire. Metal in proximity to LI will cause the oscillator to shift frequency. An AM transistor radio is used to detect the frequency shift...
The project is designed to develop a robotic vehicle that can sense metals ahead of it on its path similar to sensing land mines. The robot is controlled by a remote using RF technology. It consists of a metal detector circuit interfaced to the control unit that alarms the user behind it about a suspected land mine ahead. An 8051 series of microcontroller is used for the desired operation. At the transmitting end using push buttons, commands are sent to the receiver.....
Here is a simple metal detector with TDA2822 and few NPN transistors. There is a small arrow connected from the Emitter of the T3 to the 10n Capacitor C4. That arrow is simply indicating signal flow as right to left in that particular wire, which is different from the remaining circuit's left to right. ..
This battery-powered metal detector uses four exclusive-OR gates contained in the 4030 CMOS integrated circuit. The gates are wired as a twin-oscillators and a search coil serves as the inductance element in one of the oscillators. When the coil is brought near metal, the resultant change in its effective inductance changes the oscillator's frequency. Gates A1 and A2 form the two oscillators which are tuned to 160 and 161 kilohertz respectively. ..
This circuit is on oscillator with LI being a 4 diameter coil of 35 turns of #26 magnet wire. Metal in proximity to LI will cause the oscillator to shift frequency...
Locator uses a transistor radio as the de-tector. With the radio tuned to a weak station, adjust Cl so the locator oscillator beats against the received signal. When the search head pas¬ses over metal, the inductance of LI changes thereby changing the locator oscillator's fre¬quency and changing the beat tone in the radio. The search coil consists of 18 turns of #22 enameled wire scramble wound on a 4-in. diameter form. After the coil is wound and checked for proper.....
The metal locator uses a one-transistor oscillator and an AM radio to detect metal. Transistor Ql is a pnp transistor that is connected to an oscillator. Resistor Rl provides the correct base bias and capacitors C3 and 04 and the search coil determine the frequency of oscillation. Capacitors C3 and C4 are fixed in value, but the search coil is an inductor that varies in inductance (and thus varies the oscillator frequency) as metal is brought near it. The oscillator.....
This metal detector circuit needs to be powered using a 9 volts power supply ( DC) or a 9 volts battery . The C1 capacitor is a variable capacitor with a value of 365 pF , C2 is a 100pF silver mica capacitor , C3 is a 0.05 uF disc capacitor and the C4 is a 4.7 uF capacitor . The Q1 transistor can be RCA SK3011 npn transistor or equivalent type and all resistors need to be ½ watts ...
This is the design of simple circuit diagram of a low cost metal detector using a single transistor circuit and an old pocket radio. This is nothing but a Colpitts oscillator working in the medium band frequency and a radio tuned to the same frequency. This is the figure of the circuit...
These metal detector circuit diagram is based on the TDA0161 monolithic integrated circuit , designed for metallic body detection by detecting the variations in high frequency Eddy current losses. For detecting metals , TDA0161 require an external LC tuned circuit . Output signal is determined by supply current changes. Independent of supply voltage, this current is high or low according to the presence or the absence of a close metallic object. This metal detector.....
The Meter and other small circuit differences, gives better performance. On the Schematic, I show Two Possible Coils. 1) The Ferrite Rod, creates an Accurate Pin Point. But it also has a Very Narrow Detection Field. 2) The Dual Wound "Tesla Coil" Creates a Wide Field of Detection. With Maximum Sensitivity at the Center of the coil. Detection of metal is with a Meter and LED. The Meter Gives a Much Better Sensitivity...
The circuit described here is that of a metal detector. The opera- tion of the circuit is based on superheterodyning principle which is commonly used in superhet receivers. The circuit utilises two RF oscillators. The frequencies of both oscillators are fixed at 5.5 MHz. The first RF oscillator comprises transistor T1 (BF 494) and a 5.5MHz ceramic filter commonly used in TV sound-IF section. The second oscillator is a Colpitt’s oscillator realised with the help of.....
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