Circuit Very simple touch switch sensor circuit diagram project Schematics

A touch switch sensor can be built using this simple electronic from the figure below. The touch switch sensor is built using a CMOS circuit, a resistor and a capacitor.
When the voltage separation stage (CMOS) is connected to the ground by touching the bottom contact, the output goes to logic state 0. This state is maintained until the sensor is touched up. Capacitor C1 make out to be continuously in 1 state after connecting the logic supply voltage. This circuit can be supplied with a DC voltage between 3 and 15 volts.

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Circuit Double symmetrical power supply circuit diagram Schematics

If you wish to use a double power supply but don’t have a center trapped transformer you can use an electronic circuit in the following configuration. This electronic circuit uses a second rectifier bridge coupled with secondary coil of the transformer using two capacitors (C1 and C2). Because the DC voltage produced is not in galvanic contact with the terminals of the transformer, where is connected the other one bridge rectifier, both voltages can be combined into a symmetric voltage.
Operating voltage of capacitors must be at least equal to the peak voltage of the transformer.

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Circuit LM723 0-30V adjustable power supply Schematics

A simple adjustable power supply can be made using LM723 voltage regulator.
This adjustable power supply built with LM723 provides output voltage between 0 and 30 volts at a maximum current of 1 Amp. Because the standard LM723 circuit minimum output voltage is 2 volts, to the ground of the integrated circuit terminal (pin 7) is applied - 4.7 volts, using Zener diode D4. R8 resistor limits the maximum output current, which in this case is 1 ampere.
With potentiometer P3 can be adjusted maximum output current continuously.
Before first use the adjustable source must be configured as follows:
Connects at output a resistance with value 1k/1watt and rotates potentiometer P3 the least resistance. At this point potentiometer P2 is adjusted so that the cursor to find the output voltage. If the adjustment of P2 does not reach up to 30 volts, can decrease the value of R6. Transistor T3 requires mounting on a corresponding heatsink (2 degrees / watt).

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Circuit 5 volt CV CC charger using LinKSwitch Schematics

A very simple 3.25W CV/CC charger can be designed using LinKSwitch || family IC manufactured by Power Integrations. This electronic circuit project is designed to provide a 5 volts output at a maximum current of 650mA . This 3.25W CV/CC charger , needs to be powered using a AC voltage between 85 and 265 VAC . The AC input power is rectified by diodes D1 through D4. Bulk storage capacitors C1 and C2 filter the rectified AC. Inductor L1 forms a pi (π) filter with C1 and C2 to attenuate conducted differential-mode EMI noise.
The LinkSwitch-II device (U1) incorporates the power switching device, an oscillator, a CC/CV control engine, startup circuitry, and protection functions into one IC. The integrated 700 V MOSFET allows sufficient voltage margin for universal input AC applications.
Transformer T1’s secondary is rectified by D6 and filtered by C6 and C7. A Schottky barrier-type diode was selected for higher efficiency.
Transformer T1 must be an TF-1613 type, manufactured by Shulin Enterprise or it can be designed using the following information .

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Circuit Noise attenuator for FM stereo broadcast Schematics

Using electronic diagram shown below can be made a very simple noise attenuator. The noise attenuator useful in FM reception, if the distortion occurs in some stereo broadcasts that disappear when switching from stereo in mono mode.
This effect is because, in most stereo reception of sound from left channel are in opposition with the right channel.
After connecting of the two channels in parallel (stereo to mono connection), the noise of the two channels cancel each other.
Montage use fewer electronic components and is based on transistors.
The entire assembly is powered by a DC voltage between 15 and 30 volts.

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Circuit Electronic Security Door Schematics

Security Door Kit

The garage door is the largest moving object in a home and should be properly adjusted in order for the safety reverse system to function properly.

With this project shows how to build a single button code lock for your garage door. The electronic lock is build around an ATtiny13 and code is written in Basic.

wait for the next LED flash, once all the digits are entered the UC checks for the proper code and opens the door and the code can be changed by pressing a button on the circuit board. It was measured 34V which is right at the top of my acceptable input voltage for the LM7805 regulator.

Security Door Circuit

My garage door opener is quite old, but it has the connections I need. I measured 34V which is right at the top of my acceptable input voltage for the LM7805 regulator. I figured out what each of these terminals is for by studying the aftermarket wireless opener module that attaches here.

This came with a set of storage containers and has already been heavily used for food. Now it’s got a new life. I don’t think I need a heat sink for the voltage regulator but I came across a small piece of threaded aluminum angle bracket from an old project so I threw it in.

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Circuit Laser DIY Schematics

Laser DIY Kit

No DIY espionage kit is complete without a long-distance listening device, and no DIY long distance listening device is complete unless it uses a sweet laser in some form or fashion.

If you agree with that statement, then you're in luck, because the following project will show how you can use a laser pointer to hear noises from hundreds of feet away.

material : Laser pointer, Old pair of headphones, Cadmium Sulfide Photocell (available at most Radio Shacks or electronics store), Tripod, Binder clips or duct tape, Laptop or other recording device.

Clip the earphones off your old headphones, and strip back the protective conduit to expose three wires (red, white, and black).

Laser DIY Circuit

There are two contacts on the photocell. Solder both the red and white wires to one contact, and the black wire to the other.

Plug the headphone jack into your laptop or other recording device. Using binder clips or duct tape, secure the photocell to something sturdy so that it can be easily moved and aligned.

Again using your clips or tape, attach the laser to your tripod and secure the power button so the laser remains on.

Find a room with a window you'd like to spy on, and aim the laser at the window at an angle. Determine where the laser reflects, and situate your photocell so the reflected beam hits the front of the cell.

Any noise from inside the room will cause the window to vibrate, which will get picked up by the laser and photocell. You might have to process the raw input to remove unwanted noise and isolate the voices. Check out the cool video to see it in action.

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Circuit Fm Wireless Microphone Circuit Schematics

Easy FM wireless microphone

This FM wireless microphone is easy to build and has a large benefit of transmission (about 300 meters, while outdoor). Regardless of its small component count and 3V operating voltage that will easily penetrate the excess of some floors of an apartment development. It can be adjusted everywhere, while in the FM band (87-108MHz) and its transmissions can be picked up at any ordinary FM receiver. The coil (L1) should be about 3 mm in diameter, with five rounds of 0.61 mm copper wire. You are able Tx frequency range by simply adjusting the distance between the coils. The antenna should be half or quarter of an extended wave (100 MHz 150 cm or seventy-five centimeters).

FM wireless microphone circuit description: The audio amplifier stage (T1) is a conventional common emitter amplifier. The 47nF capacitor isolates the microphone from the base voltage to the transistor and only allows AC signals to pass. The LC tank circuit T2 occurs, the feedback capacitor C5 and the parallel LC circuit L1, C4. The coupling capacitor (C6) directs the signal to your amplifier RF (T3).

FM Wireless Microphone calibration circuit: Location of the transmitter 10 feet of a FM radio. Place the radio in a 89 to 90 MHz Spread the coil in the coil L1 frequency tuning also sought.

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Circuit 30W VHF FM Broadcast Amplifier Schematics

The 30 watt amplifier circuit shown below provides an appropriate power boost with an input of 4 watt up to 6 watts. The circuit is designed to cover 88-108MHz FM Broadcast Band. However, the circuit is very stable at my place and provides a clean-output through seven (7) element Butter-worth low-pass filter.

The heart of the circuit is 2SC1946A VHF RF power transistor. The transistor is specifically designed to operate at frequencies up to 175 MHz, with very good results.

The feedline is decoupled. The current amplifier can be more than 5 amps. All coils are made of 16gauge wire rod (copper or silver wire can do better) and HF RFC may be central torus (as shown in the image) or 6-hole ferrite R1 bead.C3 and snubber circuit forms, while R2 and C6 prevent the amplifier self-oscillation in VHF, it is sometimes necessary to add 180 ohms in parallel with the amplifier will L7.That to dispel UNDESIRABLE VHF thereby reduce the spurious level.

The 60Watts VHF power amplifier using the above circuit. 2SC1946A Two transistors are arranged at 90 degrees to each other and their results were combined using "Network Power Combiner". It is very difficult to combine skills in the VHF and UHF

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Circuit Discrete Voltage Inverter Schematics

Discrete Voltage Inverter

The circuit in the diagram enables a negative voltage to be derived without the use of integrated circuits. Instead, it uses five n-p-n transistors that are driven by a 1 kHz (approx) TTL clock. When the clock input is high, transistors T1 and T2 link capacitor C1 to the supply voltage, UIN, which typically is 5 V. During this process, transistor T5 conducts so that T3 and T4 are off. When the clock input is low, T5 is cut off, whereupon transistors T3 and T4 are switched on via pull-up resistor R6 and either R4 or R5.

This results in the charge on C1 being shared between this capacitor and C2 Since the +ve terminal of C2 is at ground potential, its –ve terminal must become negative w.r.t. earth. The high level at the clock input must be of the same order as the positive input voltage, UIN, otherwise T1 cannot be switched on. The clock frequency should be around 1 kHz to ensure a duty cycle ratio of 1:1. Altering the ratio results in a different level of negative output voltage, but this is always smaller than that with a ratio of 1:1.

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Circuit Two-Wire Temperature Sensor Schematics

Two-Wire Temperature Sensor

The Type LM35 temperature sensor from National Semiconductor is very popular for two reasons: it produces an output voltage that is directly proportional to the measured temperature in degrees Celsius, and it enables temperatures below zero to be measured. A drawback of the device is, however, that in its standard application circuit it needs to be connected to the actual measuring circuit via a three-wire link. This drawback is neatly negated by the present circuit. When the LM35 is connected as shown, a two-wire link for the measurement range of –5 °C to +40 °C becomes possible.

Actually, the circuit shown is a temperature-dependent current source, since it uses the variation of the quiescent current with changes in temperature. The values of resistors R3 and R4 are calculated to give an output voltage of 10mV °C–1. Where good accuracy is desirable or necessary, 1% resistors should be used. In this context, note that a loss resistance in the link between sensor and measuring circuit may cause a measurement error of about 1 °C for every 5 ohms of resistance. Capacitor C1 eliminates undesired interference and noise signals. At an ambient temperature of 25 °C, the circuit draws a current of about 2mA.

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Circuit Mains/Fuse Failure Indicator Schematics

Mains/Fuse Failure Indicator

The indicator shows when the mains is present at its output by a continuous glow of a neon bulb, La1, and when the fuse is blown by flashing of the neon bulb. When the fuse is intact, capacitor C2 acts as the series resistance for the neon bulb, so that this glows continuously. When the fuse has blow, the mains voltage across diode D1 is applied as a pulsating direct voltage to network R1-C1. Capacitor C1 charges slowly and when the voltage across it reaches 80–100 V, the neon bulb comes on. Capacitor C1 is then discharged slowly via diode D2 and the bulb.

When the voltage across it has dropped sufficiently, the bulb goes out, whereupon C1 slowly charges again. This process repeats itself, so that, provided the values of R1 and C1 are right, the bulb flashes visibly. The potential across capacitor C2 is a ramp with a peak value of 30 V (which is, of course, applied to the load). Note that the neon bulb used for this purpose must not be a type that has a built-in series resistor.

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Circuit Remote Control Circuit using NE555 & LM567 Schematics

Remote control circuit consists of two parts, one is the transmitter and the other is the receiver. A simple schematic diagram of the remote control. IC transmitter transmitter circuit is controlled by NE555. Receiver circuit works by the frequency of the signal, which is emitted by the transmitter circuit. Transmission frequency of the signal must be equal to the decoder frequency receiver circuit. The frequency generated NE 555 is the same as the receive frequency of the IC LM 567.

Resistor R1 is a variable receiver to facilitate the adjustment process. The system works well when the circuit is ready. The first step is the optimization through the transmitter is turned on continuously, while the receiver R1 to set the value of being able to detect the signal from the transmitter. The second part is the receiver is controlled by LM 567. The following is a schematic drawing receptor.

In the image at the top of each channel is designed with a different frequency. Given the bandwidth of the frequency detection signal LM 567, between the frequencies on which they owe a big enough difference, let's try with a difference of 5 KHz.

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Circuit Metal Detector using CS209A Schematics

This metal detector using CS209A made by Cherry Semiconductor. The CS209A is a bipolar monolithic integrated circuit for use in metal detection / proximity sensing applications.The CS209A metal detector IC has two on-chip regulators current, the oscillator and low-level feedback circuits, peak detection / demodulation circuit, a comparator and two complementary stages.The oscillator output, along with an external LC network provides controlled oscillations, where the amplitude is highly dependent the Q of the LC tank. The demodulator senses the negative peak of the oscillator wrap and provides a demodulated waveform as input to the comparator. The comparator sets the state of the complementary outputs by comparing the input of the demodulator to an internal reference.

The detector is a single coil 100uH. The IC has an oscillator integral part of the strangulation of an external LC circuit is the inductance that is changed by the proximity of metal objects. Is the change in the oscillation that is amplified and demodulated. LED 1 will light and the buzzer will sound when the inductance has changed. Installation is easy: R5 is adjusted with the LC away from any source of metal for the LED lights and buzzer. The control is reversed so that the LED turns off and stops ringing. When the shock comes in contact with a metal object that alters its inductance, LED and buzzer are activated.

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Circuit Basic Inverter circuit diagram Schematics

This is the bacis of inverter circuit diagram. The circuit will convert 12V DC to 120V AC. This circuit can handle up to 1000Watts supply depends the T1, T2 and transformer used. Please see the note.

Component list:

Part	Total Qty.	Description	Substitutions
C1, C2	2	68 uf, 25 V Tantalum Capacitor
R1, R2	2	10 Ohm, 5 Watt Resistor
R3, R4	2	180 Ohm, 1 Watt Resistor
D1, D2	2	HEP 154 Silicon Diode
Q1, Q2	2	2N3055 NPN Transistor (see “Notes”)
T1	1	24V, Center Tapped Transformer (see “Notes”)
MISC	1	Wire, Case, Receptical (For Output)

Notes:

1. Q1 and Q2, as well as T1, determine how much wattage the inverter can supply. With Q1,Q2=2N3055 and T1= 15 A, the inverter can supply about 300 watts. Larger transformers and more powerful transistors can be substituted for T1, Q1 and Q2 for more power.

2. The easiest and least expensive way to get a large T1 is to re-wind an old microwave transformer. These transformers are rated at about 1KW and are perfect. Go to a local TV repair shop and dig through the dumpster until you get the largest microwave you can find. The bigger the microwave the bigger transformer. Remove the transformer, being careful not to touch the large high voltage capacitor that might still be charged. If you want, you can test the transformer, but they are usually still good. Now, remove the old 2000 V secondary, being careful not to damage the primary. Leave the primary in tact. Now, wind on 12 turns of wire, twist a loop (center tap), and wind on 12 more turns. The guage of the wire will depend on how much current you plan to have the transformer supply. Enamel covered magnet wire works great for this. Now secure the windings with tape. Thats all there is to it. Remember to use high current transistors for Q1 and Q2. The 2N3055′s in the parts list can only handle 15 amps each.

3. Remember, when operating at high wattages, this circuit draws huge amounts of current. Don’t let your battery go dead .

4. Since this project produces 120 VAC, you must include a fuse and build the project in a case.

5. You must use tantalum capacitors for C1 and C2. Regular electrolytics will overheat and explode. And yes, 68uF is the correct value. There are no substitutions.

6. This circuit can be tricky to get going. Differences in transformers, transistors, parts substitutions or anything else not on this page may cause it to not function.

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Circuit DC Power Delay based on SCR Schematics

The circuit diagram shown here is a simple circuit DC power delay, which is based on an SCR (Silicon-Controlled Rectifier). This circuit is very useful and can be used in many applications. The operation of this circuit is very simple. When input power is applied to the capacitor C2 charges through resistor R2 when the voltage on the capacitor just above the voltage of the Zener diodes D3 breaks, breaks and H1 SCR is triggered and the power delay will be available in late OUT.

Notes.

• The circuit must be assembled on a good quality PCB.
• The Zener diode must be rated half the input supply voltage.
• The current capacity of the circuit depends on the SCR and here it is 4A.

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