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Video Activated Relay
This simple circuit from the May 1996 Think Tank column of Popular Electronics activates a relay when it senses a composite video signal. This allows you to use the tuner built into your VCR to turn on and off older TVs that are not equipped with a remote. It can also be used to activate surround sound equipment, turn off the room lights, turn...
Optical switch detector with 555
When the phototransistor is stroken by IR light it conducts and the voltage between the 1Mohm resistor(arbitrary) and the phototrans drops from VCC to lower values. When the voltage drops lower than VCC/3 the 555 is triggered and goes high (from 0 TO VCC). The amount of light that strike the phototrans necessary to bring his collector to VCC/3...
Phone line in use drives Relay
Circ?it to close a relay when any phone extension is off-hook. Uoltage at the gate of the MOSFET sho?ld be negative (1-3 volts) with respect to the so?rce then phones are on-hook. Uoltage at the gate sho?ld be positive (8-113 volts) with respect to the so?rce (gro?nd) then any phone extension is off-hook. ? high impedance meter is needed to...
AC current Detector schematic
This circuit will detect AC line currents of about 250 mA or more without making any electrical connections to the line. Current is detected by passing one of the AC lines through an inductive pickup (L1) made with a 1 inch diameter U-bolt wound with 800 turns of #30 - #35 magnet wire. The pickup could be made from other iron type rings or...
Logic level relay controller
The schematic below illustrates 4 methods of controlling a relay with a digital logic signal. Figure (A) can probably be used in most cases where the relay coil requires 100 mA or less and the input current is 2 milliamps or more. The resistor value (R) is determined from the input voltage and the available current. For example, a 5 volt input...
Monostable to bistable relay with momentary switch
This circuit could be used to drive a monostable relay by a singol momentary switch. Powered by 24 Volts it works for a 12 Volts relay. When the button is pressed Q1 is energized and the capacitor charges, while the relay coil is shorted. Once the button is released the relay turns on. Note that Q1 is powered by the capacitor until the relay...
Two buttons Safety relay
This circuit turns on a relay when two buttons are pressed at the same time.The relay backs off after few seconds, then the buttons have to be released and pressed again. This feature is often required in industrial safety.
Light/Dark Switch With Relay
The circuit as shown act as a light detector. Under normal conditions the resistance of the LDR is high, keeping pin 2 low. When light falls onto the LDR the resistance drops to a couple hundred ohms and triggers pin 2 high which biases the base of Q1 via pin 6 and R4 and in turn activates the relay. Light/Dark switch Circuit with relayAs.
BC337 Light Relay Switch By BC547 &
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Mini Voice Operated Relay circuit diagram
This is the circuit diagram of a voice operated relay. It similar with sound activation switch circuit which will turn on and turn off (connect and disconnect) the switch depending on the sound input. The output switch of this circuit is act by a relay. You could change the release time constant (C2 & R5) to say 30 seconds and use the VOX as a lig
Energy Saver Relay Coil circuit and explanation
Some relays will become warm if they remain energized for some time. The circuit shown here will actuate the relay as before but then reduce the hold` current through the relay coil current by about 50%, thus considerably reducing the amount of heat dissipation and wasted power. The circuit is only suitable for relays that remain on for long perio
Relay Selector Pushbutton circuit and explanation
This circuit was designed for use in a hifi showroom, where a choice of speakers could be connected to a stereo amplifier for comparative purposes. It could be used for other similar applications where just one of an array of devices needs to be selected at any one time. A bank of mechanically interlocked DPDT pushbutton switches is the simplest w
240Z Headlight Relay Mod
The following is my modification of the Headlight wiring for 240Z`s. I made this modification in order to take the current load off of the Headlight switch and put the load onto two relays, giving more current to the lights at the same time. This circuit is intended to be installed by splicing it into the stock 240Z wiring harness on the right fen
As explained elsewhere in this article set, after an equipment failure I decided to replace a combination inverter/charger unit with individual components that fill the same needs. The combination unit (the "Everything Box") is an efficient way to save costs by combining certain electronic functions and sharing hardware, but if it should fail, all
Relay Timer with ATmega8
Timers are widely used in industrial and domestic application for automating tasks. Microcontrollers can be used to design versatile and accurate timers with.
Individual benefit of solid-state relay (SSR) above normal electro-magnetic relay (EMR) is its tear and wear emancipated surgical treatment. S201S01 from clear-cut is a superior paradigm. at this juncture is the circuit diagram of a DIY SSR project, which is all the rage truth an isolated triac power controller. The switching output from one dc ci
Motor Driver Circuit
Remove the 6 mm screw holding on the lower rear fairing cover. This is the black plastic piece the spark plug protectors are attached to. Do not remove the lower rear fairing covers, only the machine screw. Fabricate "L" brackets from the mending plates to mount your horns. I bent my mending plates in a vice and enlarged a couple of the holes to f
Water Activated Relay circuit board
Circuit diagram is water activated relay circuit. In this diagram circuit using two transistors connected as a high gain compound pair. 2N2222A transistors T1 and T2 may be a BC108. Current gain will be the product of each transistor beta, which will be a minimum of 140 x 110 or 15, 400. Power supply voltage can be used 4, 5-15 volts, a typical...
Dark and Light Activated Relay
The potensiometer adjust the trigger on` level. The diode in the circuit diagram shows to be 1N914. This is ok if you have a light-duty relay, also the 1N914 is a signal diode so actually does not qualify. Use a 1N4001 (or better) instead. A couple of substitutes for the 2N2222 transistor are: NTE123A, ECG123A, PN100, etc. Tags: 1N914, 2N2222, dar
solid state relay
A Solid State Relay is in reality not a relay after all. There`s no `relay` found, just the electronics circuit which does the switching. It operates a similar way as a relay; it is possible to use a low voltage to switch a higher voltage or better than ordinary relay. This `relay` is placed in. This circuit diagram is quite simple and cheap. Amp
Automatic Inverter Supply and Mains Supply Changeover Relay
I have been put forth with this question many times in this blog, how do we add a change over selector switch for automatic toggling of an inverter when AC mains is present and vice versa and also the system must enable automatic switching of the battery charger such that when AC mains is present the inverter battery gets charged and when AC mains
Parallel Port Relay Interface Circuit
Below are three examples of controlling a relay from the PC`s parallel printer port (LPT1 or LPT2). Figure A shows a solid state relay controlled by one of the parallel port data lines (D0-D7) using a 300 ohm resistor and 5 volt power source. The solid state relay will energize when a "0" is written to the data line. Figure B and C show mechanical
Mini Operated Voice Relay Schematic
This mini-VOX voice operated relay is based on a circuit published in Silicon Chip, 9/1994, p31. The off delay time may be adjusted by varying R3 and R4. Reducing R3 will result in a longer release time. You could change the release time constant (C2 & R5) to say 30 seconds and use the VOX as a light switch with this delay time before turn
8 Relay Control Circuit Schematic Diagram
Control Relay Circuit with 9 Second Schematic Diagram
Amplifier Output Delay with Relay Schematic Diagram
This is a minimal circuit which I built to individual of my audio amplifier projects to control the presenter output relay. The end of this circuit is to control the relay which turns on the speaker output relay within the audio amplifier. The impression of the circuit is time lag around 5 seconds ofter the power up until the speakers are switched
Using Solid State Switches Instead of Mechanical Relays
Mechanical 12 Volt DC automotive relays are used throughout the car audio industry to turn on amplifiers, lock doors, roll ‘up windows, etc. However, there is another way to activate such loads, and that way is to use solid state switches. Why would anyone want to replace a mechanical relay that is so depend able Well, for starters, the coil in
555 (TLC555) Relay Driver Circuit
Many integrated circuits have undocumented features or abilities. This is one of them. The TLC555 output (pin 3) can sink a 100mA load to 1. 28V. The open drain transistor reset (pin 7) can sink 100mA to 1V. Tying both lines together is permissible because they are logically the same polarity and this potentially doubles the sink current ability to
555 Voltage Doubler Relay Driver
These novel relay driver circuits have the ability to pick up a relay with a coil voltage rating equal to double Vcc. After pickup, the relay armature is held via the application of Vcc. Under this condition, the coil power is reduced by the square of the voltage ratio, or to 25%. This is the ultimate in relay economy ”the reduction of wasted coi
Automatic Battery Charger 6V-12V with Relay cut off by LM324
This be battery charger the automatic circuit again interesting circuit. Because of use IC LM324 then make economize. And can charger get both of battery 12V sizes and 6V with the filtration that at S1. Certainly circuit this still base property be when battery have voltage full already, circuit as a result order give Relay RY1 cut the system depa
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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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