Top Circuits Page 123
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12V of power, and wanted to power LEDs with a forward voltage of 2V, could I only power 6 of them Would I connect the cathode of one to the anode of the next, creating a kind of serial connection Or is there a way to have each LED be it`s own loop Thank you.....
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The chip in the middle with the tiny bullet holes in it is almost certainly proprietary. At best you can salvage a few parts if your time is worth nothing, but you don`t need to know the circuit for that. Olin Lathrop Apr 9 `13 at 14:24 Just to make sure:....
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The circuit above is the canonical AC coupled common emitter amplifier which is typically used as a linear amplifier, not a switch that "turns on" when the input is above some level. Alfred Centauri Apr 9 `13 at 19:26 Edit you question to reflect what you`re....
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A phase shift oscillator, using a CE Amplifier. I have a Vc of approximately 6V, gain of approximately 40(>29, as required). I aim for an oscillation frequency of 1. 5 kHz...
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What kind of microphone or mouthpiece I can use to connect across a pots telephone line in order to send dtmf tones ( no voice ) dtmf only. Can I use a regular mic or does it have to be a certain type, I am using a 300 ohm resistor to hold open the line....
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Soft power switch for a microcontroller where a momentary switch can turn the circuit on (including microcontroller), and then when the switch is pushed a second time, the microcontroller can shut itself off after performing some clean up. I have the above....
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Make a 0-25 mA current limiter. I want to take a control voltage of 0-5 V as input and have it control a current of 0-25 mA through a restive load (the restive load may vary between 0-200, it`s represented as R2 below). The O2 op-amp is used to make a....
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First I tried connecting the circuit to a 9V battery. (Multimeter reads around 8. 3 Volts, which is in the operating voltage range of the LM386 as per datasheet) The result I have is lots of noise, sometimes cracks and pops and a barely audible sound of the....
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Unit is driving 80V/10A motor. I currently use the following matching rigg, but since MOSFETs isn`t my domain I`m abit uncertain of the validity of the matching in accordance with the application...
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Power a 12v fan using a darlington so I can control the speed from an Arduino. When I wire up as below nothing happens, even though I`m sending a PWM signal: Please draw a proper circuit. Edit your question and hit Ctrl+M, the current image is unreadable.....
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The circuit has educational purpose, so being simple is a must. I`m also trying to build it only with components that I already have (a bunch of resistors, capacitors, transistors and none IC)...
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The resistance of my heater is made of 9$Omega$ 3mm diameter nichrome wire. On 240V(rms) voltage this makes 25A(rms) current. I have an access to a mains line capable of delivering 30A, so in theory I will be able to drive heater at full load. In reality I....
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An Oscillator circuit which can produce a good sine wave with a frequency of at least 500 Mhz. This is for RFID applications. I have tried to use an class E oscillator, but i cant seem to get the design right. Can anyone help me out..
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Using a single-coil latching relay, which latches/resets with opposite polarities. I`ve tested the circuit with dual opposite-biased LEDs too, no light flicker in either direction to indicate a charge/discharge. QuadrupleA Apr 14 `13 at 23:14 Unless there`s....
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Turn on a "black box" of leds (that operates at 8-9v) when my motion sensor is activated. The problem I`ve got is that the output of my PIR is only 3. 3 volts. Here is my crappy schematic. There are a few things that need to be fixed. First, A resistor is....
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It can`t be 0 volts, since the current does not freely move around, due to the resistor; resulting in one side being more negatively charged, and the other more positively charged, since the electrons can move faster to an end of the battery than through the....
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Just a nitpick, you don`t have the Leds in Parallel with the transistor. If you did, the leds would be on when the transistor is off. You have them in parallel going into the transistor. All the transistor sees is n times led current going through it. It....
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Take the input from a microphone and use it to power an LED, so that it`s off at ambient sound, and (the peak brightness) gets brighter with noise level. It`s okay if it flickers, I`m just trying to get the peak voltage to be proportional to sound levels.....
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Make a circuit with a 555 timer to run 72 LEDs all at the same time. I have already made a circuit, but am not sure If it will work safe and long or not. I am putting the picture of the circuit and I want anybody who can help to look at it and see if it....
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An op-amp based Colpitts oscillator in multisim. When I press run button it shows- "timestep too smaall error". I`ve googled and tried everything but it still shows the error. Not sure where you got that design, but as drawn your C-L-C pi circuit is grounded....
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A drink mixer inspired by BAR2D2, I am using a gravity fed pump that is capable of running on a 9v battery. I am using a circuit with a 555 timer to control how long the pump will run. When I hook the pump directly to the battery the pump runs perfect. When....
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VOUT to be 3V when the switch is open and 5V when the switch is closed. The simulation seems to give me what I want when the switch is open, but not when it`s closed. What am I doing wrong Is there a better way to do this I was avoiding a common cathode....
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A bicycle light control circuit which reads in various buttons and sets various outputs accordingly such as headlight, taillight, blinkers, etc. My current design is based around an ATtiny24 ( Datasheet ) using the internal oscillator (8MHz), programmed in C....
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The amplifier in the following schematic, when simulated, shows that it can cleanly amplify a signal with 0. 1V amplitude to 10V. When driven with a larger signal, though, the behavior is very nasty in the positive half cycle. The output suddenly dives from....
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You already appear to have sufficient snubberring around the TRIAC which should eliminate DV/DT based switching (the TRIAC turning itself on due to noise on the gate lead) which I believe that your issue is on the micro side of things. I think your issue is....
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Red = V+, Black = V-, Green = GND, Yellow = Mic Input, Orange = LED Output. The op-amp I`m using is an LM741. It`s supposed to change the peak brightness of the LED depending on the ambient sound level. The frustrating thing is that the simulator is happy....
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There are three switches that represent "binary number", and according to that switches` combination, number of lit LEDs change to represent that binary number. I am wondering how do provide equal current and voltage for LEDs and make them light up with....
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A board design that is supposed to measure a loadcell. We have finally tracked a system accuracy fault down to the amp IC. When we twist the board, the amp IC changes its output. I get +80mV when I twist the board from its 4 corners. I`m using the amount of....
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Understand how come the LED will not light up as the Capacitor looks like it`s by-passing the switch. When the capacitor is full, it doesn`t transmit/conduct electricity You`ll notice that I`m very beginner, but after 20 hours of reading various tutorials, I....
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A 12v battery is being charged from a solar panel. When battery is 12v solar panel is disconnected from battery and connect the load with battery. And again solar panel is connected with battery when battery voltage is say 10v. How to switch simply Which one....
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Bold lines are soldered connections, arrows are wire based connections. Red for V_cc, Black for ground, blue for intermediate connection and gold for primary output. Pins 1, 5 are connected to ground (I recognize that 5 should go to a capacitor to ground,....
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If they have to be both powered from the battery do I need to connect the emitter to the ground of the Arduino AND the battery to stop all the current from flowing through the Arduino ground and get a clean pulse or do I just connect the emitter to the....
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The circuit includes a shift register chip (74HC595N), which I couldn`t find on CircuitLab. Is there any specific drawing to represent a shift register on a schematic I can`t help you with circuitlab, but if you just want a schematic picture, you can take a....
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Actually this part of the circuit is isolated from any other component (except via 5v & ground). Other than that, you can find LEDs and a shift register, but I guess they do not interact much. Or do they The ldr is used only as a light sensor. is there more....
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First I convert the Delta R2-R3-R4 to Y (wye), because the Voltage divider should be used in a series circuit so I tried to convert the delta to series, but that just work for find the total Resistance. so in this case $$V_{out} = V_{R_2}$$ I am using....
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The transistor shown is a P-channel MOSFET acting as a "high-side switch". More commonly, an N-channel MOSFET low-side switch is used, but what you have will work as long once you add something to the drain such as in this image of P-Channel MOSFET switch....
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Used several KE 4-211-2 Sennheiser microphones to assemble a device for acoustic signal analysis. They are connected to a National Instruments data acquisition device with ~1 m long cable and sampling rate is set to 50kHz. I`ve added a resistor and a....
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It`s built on a breadboard and it sounds exactly how it should sound (damped sine wave, big 808/909-kind of kicks). However it`s noisy. I`ve tried adding a big electrolytic cap between V+ and GND. It makes difference yet it`s still very noisy. Also, the....
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When the motor is connected in this fashion, the netduino activates the transistor, but nothing happens. If i swap the motor with an LED, the LED does light up, so that incidates that the motor isnt getting enough power. So i connect the motor direct to....
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A scoreboard in the middle of the room, that one will control from backstage. The scoreboard will have two 3-digit numbers, controlled individually. Whenever the score changes, a little irritating sound should. sound. What is the easiest, more efficient and....
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It should default on when first connected, but if a particular signal goes high for a small amount of time (say, 10 microseconds, ) then it should turn off, and stay off. It`s the "default on" that gives me trouble. The closest I can get is something like....
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Calculated the output of the transformer to be 125 times (1000 / 8) higher than input. Since 12v is given as input, output should be 1500v (not sure about this)..
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Control RGB LED strips via a USB or ethernet interface. These strips consume a lot of power and the mass produced controllers suck. I would also like independently controllable "zones" if you will, so ideally this device could power 1 or more strips. Since a....
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The loads (2 or more solenoids in parallel) share a 12V supply and are individually switched to ground through the car`s ECU. I need to detect when any one of the circuits close (only one closes at any one time), using a single PIC digital in (or comparator....
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An R/C electric motor that has a 10K thermistor sensor built into it, which is connected to a speed control that has basic thermal protection. I would like to build a secondary sensor board that displays the temperature on a segment display, but I still want....
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The two diodes will be fried. You`ll want some series resistors for them. If the simulation runs, the current through the diodes will be huge. jippie Apr 30 `13 at 9:40 @jippie Both diodes need not be fried :-) One will become a SED (Smoke Emitting Diode),....
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There are chips that have AND/OR/NOT gates, but I was wondering if there`s a single one that have all of the ones I need - if not, then what should I use specifically Any reason it has to be those particular gates For example a package with with four NOR....
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For a project I need to display a progress bar of the activity performed by my MCU. For this purpose I am going to use a bargraph display, but the problem is that bargraph display driver driver IC LM3914 uses analog input where as MCU produces a digital....
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A strip of LEDs from a microcontroller using PWM to control the brightness. The strip I have takes about 1. 5A at 12V. I`m only familiar with purely low power digital electronics so wanted to check if these assumptions are correct and get any advice :-....
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Measure current on a constant current source(LM317), because I am using a 3v3 chip I also need a voltage divider to read it. Will this circuit work Or will it wreak havoc trying to increase voltage to drive current over the voltage dividers..
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The TPS61200 spec says GND is control/logic ground and PGND is power ground but this isn`t reflected in the symbols chosen in the diagram. I`m also puzzled why the link to earth is shown on GND rather than on PGND. From this key it seems that various parts....
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If you want to build a 7 to 128 demux with 3-to-8 and 4-to-16 demuxes, then put the 3 high bits of your output address into the 3-to-8, and use the outputs of that as the input enable to the individual 4-to-16 demuxes (assuming that it has an enable pin), so....
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It says that D1 compensates for D2`s forward drop by providing 0. 6V of bias. Is the +5V an external 5v source How does it compensate The R1, R3 and D1 basically creates a 0. 6V bias on the other side of the capacitor, so that a positive swing in the signal....
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All you need to do is supply a resistor (I used 200 Ohms, with a 3. 3V supply) to the power line, GND it, then connect the data line to one of your digital pins (I used pin #2)". However, the datasheet shows an example circuit with a 100 Ohm resistor....
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100 Ohms at 4. 5 Volts (3xAA) allows 45 mA, but at the upper end of the sweep, due to the load being in parallel, it will be much higher - basically limited by the resistance of your load and your battery capacity. So yes, you can "smoke a pot" (heh!).....
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The first option is of course a zener. I actually have a bunch of 2. 2V which would protect the capacitor fine. The problem is, of course, half the energy is going to be wasted across the diode short. Is there any way I can regulate the voltage below 2. 3V....
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Supply it with a Li-Ion cell, which has 2. 7-4. 2V. I don`t really want/need the complexity of a buck/boost converter. I know I could just regulate it down to anything below 2. 5V, but it still would be great if my circuit would get 3. 3V for Input-Voltages....
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Control a little 5v motor from an external power supply by using the Arduino to trigger a transistor. Like this: Is that at all correct Will it work I want to experiment but I don`t want to break my new toy in the process. The transistor I am using is an....
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The light is simply blinking instead of dimming. So I used the following software to just glow the bulb without dimming: unsigned int i=1; void setup() { Serial. begin(9600); pinMode(AC_pin, OUTPUT); pinMode(11, OUTPUT); attachInterrupt(0, light, RISING); }....
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A variable frequency, variably duty cycle 555 configuration in astable mode. I`m using a set of pots to get a wide range of control. It works beautifully. The output is great, but I have a problem. I am driving a couple mosfets directly from the output. But....
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Invert a signal to drive fets with hard/fast rise and fall times. I was told in another thread to use an inverter (NOT chip). This makes perfect sense to me since logic chips are always hard ON or OFF by design. But I`ve never worked with logic chips before.....
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The other transistor (T2) is controlled by the current flowing through the resistor (R1). If a DALI slave unit is connected, this current will be the same as that flowing through the power transistor. The value of the resistor is chosen in such a way that....
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I have a 4 position slide switch according to the position of the slide switch, I should turn on different colored LEDs and also vary the output frequency of 555 timer in astable mode and drive a piezo buzzer. Problem : I cant use the same switch to control....
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A high voltage power supply 3V to 500V DC converter and someone suggested a circuit from techlib H. V. generator for Geiger tubes : However, when I tried to simulate it didn`t work, the output is nearly 9V, as the input. In the schematic I drew, the only....
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A MOSFET that drives a load. The load has a sense resistor in its current path and its voltage is used to trigger a circuit that can disconnect the load if we detect an over current condition. But it wasn`t that easy. Many kinds of loads generate large....
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Control a LED with audio signal, but the problem is, that output signal is only 150mVpp (with 150mVpp positive offset). In my understanding, it needs to be higher than 0. 6V to get the transistor running, therefore I am not sure what to use instead. Do I....
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Performing a chip conversion for the Sparkfun LED RingCoder. The sample code provided with the product works well on an Arduino UNO, but it uses a pin for each I/O - 5 pins for the shift registers and 6 pins for the RGB rotary encoder. What I want to do is....
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A LED to indicate when a DC voltage reaches 5 volts or more. I don`t want the LED to be dim when it is at 4. 5 or anything. I just want it to be full bright at 5, 0 bright at anything below 5. Is there a way I can do this with discrete components (no IC`s,....
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Simple low voltage/current power supply that can accept wide range of input voltages, up to the hundreds. Let`s say, the input is 20 to 160V DC and output has to be 10V with 20ma maximum current. Since it has to be simple, I decided that it should be some....
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It`s supposed to reduce the max. voltage between the GPIO input pin and the current source to 3. 3V, since 5V * (10K/(10K+5K) = 3. 3V. The thing is - 3. 3V is the voltage over the 10K resistor and 1. 7V is the voltage over the 5K one. As long as the current....
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It takes a voltage between 0. 4 and 1. 2 V on pin 5 to control its gain. In the first two versions of the circuit, I used logic ICs and/or counters and an op amp with a resistor network for a DAC to provide the voltage, and all worked well. This last week, I....
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Charge a simple servo that only has + and - pins. Usually I would connect it`s - pin to the ground and + pin to the digital output from Arduino. This works, but the servo turns weakly and can be stopped by hand. If i connect the servo directly to the battery....
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The top channel is my signal to the gate of a mosfet. The mosfet is driving a tank circuit that contains a large coil wrapped on ferrite with a 5uF capacitor. Thecoil is large enough that the frequency is near 100Hz. The bottom channel shows the positive....
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Installing LED strips in car`s tail lamps to convert it from conventional bulbs to LEDs. This is the product I`m planning on working with and I need a length of 16", 15" and 14" to make then look correct in my housings. When I did the math the 19. 7" strips....
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The circuit is shown in receive mode, PTT switches to transmit, the speaker serves as a microphone and speaker. All systems I`ve seen use a Rocking Armature Transducer for the speaker. There is no base station or similar - you can just connect two or more of....
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A high voltage power supply for an electron beam system. The voltage regulator is an old analog system that works via a simple comparator and reference signal from a POT. My problem is the feedback voltage from the high voltage tank (tank meaning large steel....
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The first thing I need to know how C1 is related to resonance frequency f of the circuit. It seems like I can choose a frequency and I automatically get a needed value for C1. I have a lot of doubts I don`t know if the circuit constitutes a Colpitts or....
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I managed to salvage a couple of motors from a worn down old printer, and I`m unsure of how to get about connecting it to a breadboard and then to a Raspberry Pi. I`ve got a cobbler kit for my Pi that allows me to connect it up to the breadboard. I`m also....
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A power supply with frequent energy switching; but the schematic is incomplete. I should add another circuit which controls the voltage polarity converter (Four transistors). The circuit generates high frequency current pulses. @CamilStaps Actually I didn`t....
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Build an h-bridge just to reverse the current, I am controlling speed elsewhere. Can I simply wire up 2 N-Channel MOSFETs and 2 P-Channel MOSFETs into a IO pin from the MC (with resistors of course) or is it more complicated than that...
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R2 controls how fast C1 charges, and I know that at a certain point C1 will trigger Q1 and Q2 to release the 9 volts (see 2). This 9 volt burst creates the clicking sound. How does the capacitor discharge I imagine that the capacitor will slowly charge up to....
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A relay, which is energised by pulling the low side low using an NPN. I would like a pushbutton to operate the transistor (and therefore the relay) for a time (500ms ish) then deactivate it and wait for the next push (ignoring the button if held). I....
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Designing a circuit that will use a combination of switches and resistors to allow a microcontroller to identify which switch was pressed based on the voltage read and perform a switch-specific action. The design that I`ve come up with involves using a....
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An Arduino running on 2 or 4 rechargeable NiMH AA batteries. I say 2 because I might boost up the voltage to what`s needed. My problem is that this project will sometimes be plugged in and I would like the batteries to be able to charge during that time.....
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Program an ATmega1284p with my AVR Dragon and the Arduino IDE. So far I have installed mighty1284p, after writing my sketch. I compile it using the Arduino IDE and then cd into the (temporary) directory the sketch is build in. It contains the. hex file, as....
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Control a current through several current-mirror device (specifically the IREF pin on the TLC5940 ) using a single potentiometer. I`ve tried using a modified Howland current souce as in the following schematic: While this works OK with resistor values as....
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Take the voltage output from a 3. 5mm audio jack and have it light up an LED according to it`s voltage. I was going to attach the left audio cable to the base of a 2222n transistor which would act as my amplifier to trigger the LED to light. Unfortunately,....
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Control a relay from an Arduino compatible board. When I try to activate the relay from the Arduino it takes at least a second to switch closed and sometimes does not switch closed at all. Digital pin 2 of the Arduino is connected to IN0 of this circuit....
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Build as simple a circuit as possible that will pull a logic line low every time an automotive ignition coil `fires`. My first inclination is to simply attach the `negative` terminal of the coil to the base of of an NPN BJT through a current-limiting....
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Using an MC25060V2 fan, and I`d like to switch it on and off through software occasionally (i. e. not PWM or anything fancy like that). My thought is to either put an NPN BJT or a N-channel MOSFET on the low side and control it`s gate with a 5V....
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With a 9 V DC battery, it worked fine. But because of a less DC power, solenoid was not generating a powerful enough force. I modified a computer power supply as the power source. Now when providing +12 V (15. 0 A) power from it, the solenoid valve is pulled....