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Metal Detector Circuits
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AC to DC & DC to DC
Solar Cell Circuits
Micro Power Circuits
Switching Power Supplies
Light Laser LED
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Data Bus Circuits
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Current to Voltage
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RF Converter Circuits
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Video Wall circuits
TV Video Circuits
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8051 / 8052
PCB CAD Software
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555 Timer Circuits
Remote Control Toy
H Bridge Circuit
Interconnection & Timing
Digital Signal Integrity
Digital & Bipolars
Sensors & Detectors
Regulated Power Supply
4 Band Resistor
5 Band resistor
6 Band resistor
4 channel infrared remote relays
Field Loss Relays
Isolated 24V Relay Controller
This is a common control voltage in industrial and telecommunications equipment, so the relays are common in surplus equipment. Many will actuate equally well on AC or DC, which makes them an easy solution when the control voltage is switched mechancially, as in the case of limit switches or magnetic reed switch sensors. Unfortunately, they`re...
Controlling a relay with a digital logic level circuit
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 sig
Electronic Thermostat and Relay Circuit
A simple thermostat circuit that can be used to control a relay and supply power to a small space heater through the relay contacts. The relay contacts should be rated above the current requirements for the heater. Temperature changes are detected by a (1. 7K @ 70F) thermistor placed in series with a 5K potentiometer which produces about 50
Electronic Selector for 10 sources with Display-Relay Drive circuit
This is a circuit for alternative sources selection. It combines mechanical selection using a rotating switch S1, the electronic drive of the relays RL 1-10 and also the optical indication of the selection by the Display DSP1..
Single Transistor Relay Toggle Circuit
The circuit requires a double pole, double throw relay in conjunction with a single transistor to allow toggling the relay with a momentary push button. One set of relay contacts is used to control the load, while the other is used to provide feedback to keep the relay activated or deactivated. Several push buttons can be wired in parallel to...
Dual Relay Driver Board Circuit
A simple and convenient way to interface 2 relays for switching application in your project. This relay driver boosts the input impedance with a regular BC547 NPN transistor (or equivalent). Very common driver. It can drive a variety of relays, including a reed-relay. Transistor Q1and Q2 are a simple common-emitter amplifier that increases the...
Relay Timer switch circuit
A 100 second delayed turn ON relay RL1 switch, if plug power +12V in circuit. In Fig. 2 see a two range 6-60 second and 1-10 minute auto turn off relay timer circuit, with 555.
9 Second LED Timer and Relay Circuit
This circuit provides a visual 9 second delay using 10 LEDs before closing a 12 volt relay. When the reset switch is closed, the 4017 decade counter will be reset to the 0 count which illuminates the LED driven from pin 3. The 555 timer output at pin 3 will be high and the voltage at pins 6 and 2 of the timer will be a little less than the lower t
Power-On Time Delay Relay circuit
Here`s a power-on time delay relay circuit that takes advantage of the emitter/base breakdown voltage of an ordinary bi-polar transistor. The reverse connected emitter/base junction of a 2N3904 transistor is used as an 8 volt zener diode which creates a higher turn-on voltage for the Darlington connected transistor pair..
Power-Off Time Delay Relay circuit
The two circuits illustrate opening a relay contact a short time after the ignition or ligh switch is turned off. The capacitor is charged and the relay is closed when the voltage at the diode anode rises to +12 volts..
Touch Switch Activated Relay
Motor controller H-bridge using relays
To control the motor, i will be using an H-bridge with a DPDT relay like you can see on this schematic below. If you want more details, look on this..
Relay and Fuse Box
1997 Buick Century the headlight relay
I would start by making certain that no light bulbs on the vehicle are burnt out, particularly the turn signal lights, brake lights and dashboard indicator lights. Funny things happen when bulbs are burnt out. It sounds like you know your way around a meter, so begin by using the exterior light diagram and check voltages backward from the...
2001 chevy s10: indicator light headlight switchfuserelay bulbs
2001 chevy s10 headlights some times work some times dont along with dash indicator light. all other lights work fine. I have changed headlight switch, fuse, relay. checked headlight bulbs. all wires to bulbs are possitive. Yes, I took test lamp and hooked ground to one side and the other side to the wire on head light plug. test lamp came on. I...
No headlights new switchswapped relays under hood fuses under
What I would do is switch the headlight switch ON & OFF and them see if you can "feel & hear" the headlight relay clicking. This is shown in the first schematic, on the left of the diagram. The triangle at the bottom left leads to the two 15 amp fuses you checked earlier. Did you test (with a test light or meter) the "TBC" fuse in the Instrument...
2000 suburban: relay air compressor LT v i manually put power
Need to know where is the phisical location of the compressor relay. Also do you know how to test the pressure sensor on the plastic tank on the compressor assembly itself Sorry to take so long to get back with you. I have not been able to nail down the exact location of the relay with the information available tome. One source referenced that...
2004 chevy impala: relay diagram passenger side fuse block
2004 chev impala - unable to find the fuse for the rear defogger. I find the relay but both manual and actaul car diagram and passenger side fuse block show 30amp fuse - but nothing is there. Thanks, I check that fuse and it is OK. I see there is a circuit breaker on the schematics. This car does have A/C does that mean the right side (A/C) of dia
Head light high beam the dimmer relay or the fuses for that circuit
If you ground the blue wire at the headlamp switch and the lights come on the switch is bad. I know you have already checked continuity of the switch though. If I recall the relay has 2 small terminals and 2 larger ones. The one smaller one should that has no power with the relay out should have continuity to the blue wire at the light switch....
18 Pin PIC Development Board with Relays
Development board for 18 pin PIC microcontrollers with power supply circuit, crystal oscillator circuit, RS232 port, ICSP/ICD port, 4 relay output, 4 optocoupler isolated inputs.
Relay Driver Circuit
In this project, we will build a relay driver for both DC and AC relays. Since DC and AC voltages operate differently, to build relay drivers for them requires slightly different setup. We will also go over a generic relay driver which can operate from either AC or DC voltage and operate both AC and DC relays. All relays come with a voltage rating
Pushbutton Relay Selector
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
Reducing Relay Power Consumption
Relays are often used as electrically controlled switches. Unlike transistors, their switch contacts are electrically isolated from the control input. On the other hand, the power dissipation in a relay coil may be unattractive for battery-operated applications. Adding an analogue switch lowers the dissipation, allowing the relay to operate at a l
Relay Coil Energy Saver
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
SMPSU With A Relay
Switched mode power supply units (SMPSUs) are popular but difficult to build oneself as well problematic when it comes to understanding their design principles. Building your own SMPSU typically requires a lot of expertise, hard to find components and time. The circuit shown here is educational only and devised to demonstrate the principle of the
Electromechanical relay logic
In ladder logic symbolism, an electromechanical relay coil is shown as a circle, and the contact(s) actuated by the coil as two parallel lines, almost like a capacitor symbol. Given this knowledge, interpret the following ladder logic diagram: How do we know which relay contact is actuated by which relay coil How does this convention differ...
electronic temperature controlled relay
simple relay actuating circuit with millivolt sensitivity
automatic turn off relay
Stepper Motor Circuits
Remote Control Circuits
Direction Finder Circuits
Power Control Circuits
Motor Control Circuits
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...
Digital Signal Integrity
Interconnection and Timing of Digital Circuits
CMOS Circuits Tutorial