Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [tachometer]

40 questions
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Converting a tachometer signal into something a microprocessor can understand

I am attempting to build a digital dashboard for my car (a 1998 honda civic), I have run into a bit of trouble, wherein the tachometer signal is quite hairy. I was wondering if someone would lend me a hand in cleaning it up so that I can feed it to…
Patrick
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Read out tachometer from PC fan when manually turning the blades ( driven shaft )

I have a problem. I can read out the tachometer of a PC fan and convert it to frequency with just using a simple microcontroller and labview. Does anybody here have an idea how to read out the tachometer, without powering the fan? I want to measure…
jemas
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Tachometer IC that does not require zero-crossings?

I recently built the basic tachometer circuit in this LM2917/LM2907 Datasheet shown below using the 8-Pin version of the device. I realize this circuit requires a VR pickup sensor, and so the LM2907/LM2917 must rely on triggering off of…
user255591
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1 answer

Old tachometer rectifier(?) components

I'm trying to reverse engineer the intermediate circuitry of a 1960s vintage marine tachometer made by a now defunct firm called Airguide. Airguide referred to the black box as a "transmitter." The circuit works. I jimmied together a pulse…
Bill Catlin
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Spark plug pick up

This is a reformulated question to make it shorter. I would like to build a tachometer for an old moped. Since my moped has a magneto and points for ignition I must obtain the signal directly from the spark plug. I would like to obtain a clean pulse…
Blaž Umek
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What is the effect of tachometer feedback (derivative feedback) on the time constant of a control system? Does it increase or decrease?

I was going through some practice problems on Control System Modelling and came across this problem. It seems like the answer to this question is that the time constant is "reduced" but the result that we get from a quick tranfer function analysis…
erstan
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LED tachometer with PIC MCU (requires more current)

I've been working on an LED tachometer that will be installed on an open wheel race car. After putting the order through for the PCB I re-calculated the current draw and turns out the PIC's (16F877A) IO pin will not source enough current to drive 15…
user18987
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Tacho signal for LED fan monitoring

I am struggling with this problem: I have a fan whose output tacho signal is a square wave when it is running properly. If the fan stops the signal remains at its last value (either high or low). I need to a simple circuit to light up a red LED if…
amsi
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How to distinguish a DC generator from an AC generator

I have an electrical generator (a tachometer really) and I want to know how can one detect if it is AC or DC? (what if it is dead and can not be tested for its output?) I add the image if some of you guys can read Russian I
kavehmb2000
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Puzzle: diode polarity in a vintage tachometer circuit

Once again, I'm trying to reverse engineer an old tachometer circuit--1970s vintage this time. There are three diodes on the circuit board, and two have absolutely no markings whatsoever. Can anyone deduce the polarity of the two labeled with…
Bill Catlin
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Inductor ground, where to put it

So I'm building a tachometer for my car. It's pretty simple, basically I have a wire wrapped around the spark plug wire about 10 times, and the 30-50k volts travelling through the spark plug wire should be sufficient to induce a small current…
rozap
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12v PWM Fan Seems to Be Running Inversely of What It Should Be

I have a 120mm 12v Fan that is used on an Antminer S7. There are two fans on the antminer, and they both are controlled by the software built in. I had one fan break, so I replaced the fan with a similar model. It's the exact same size as the…
B-Dawg
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12 Vdc Intel fan tachometer output to 24 Vdc PLC input

I'm working on a cooling fan rotation supervision system, and I'm planning to use my old 4-wire Intel E18764 12 Vdc cooling fan to test it (as I don't have access to the 24 Vdc actual fan I'm going to eventually use) but I'm not much of an…
stmas
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3-wire fan: Minimum supply voltage for Tach signal?

I want to use a 3-wire fan (e.g. this one), which will be operated closed-loop, powered by a variable DC voltage 0-12 V with tachometer feedback. When requesting a rather low RPM of the fan, the DC supply voltage (\$V_+-V_-\$) will be probably…
tobalt
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ID a green ceramic component from a tachometer?

This component is from a 1960-70 vintage boat tachometer. It's about 1.25" long. It generates not a single reading on my 11-function multimeter (including capacitance). I may have fried it removing it from the circuit board. Thanks for any…
Bill Catlin
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