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Sal, say you have a sine wave that is 1" long , 360 degrees, start to finish, and another that starts 25% later, that would be a 90 degree vector angle, correct. If you agree, how can I plug those numbers into sin(x+q) to get 90degrees? Thanks
The phase shift is a linear dimension in which the vector angle is calculated. That is what I need to know. If I have 2 sine waves on a scope, channel A and B, and I know the phase shift, I would like to know what the vector angle is.
Look at page 5 of **broken link removed**
555 timer projects
Can I use a 555 timer in this schematic to increase the pulse rate vs. using the 2 switching transistors. With the transistor configuration, I get flicker on a scope. If not, how can I rearrainge the transistors to double the speed.
I need to know what the basics are for simple to-92 switching transistors.
Ie. On a NPN is the base always a positive voltage, is the emitter always grounded, and is does the collector always have plus voltage?
If those facts are true is a PNP just the opposite of an NPN? Negative signal on...
Re: 741 Op-amp resistors
The formulas are easy r2/r1 BUT knowing what they do is the problem. For plain inversion of the signal you want two of the same values for r1 and r2. Why use a resistor at all if the value will be 1. My signal is a 10ma modified square wave and I have tried two 1K...
741 Op-amp resistors
I read the article and that section. Very crypic and not easy to inderstand. I could not find a starting point for a 1:1 inverting signal. I guess I could start with two 1K resistors.
How do I determine what values the 2 equal resistors should be for inverting a signal without gain. Also, should the ground of the 741 also have a resistor. I have seen some examples where that is called R3 and is equivilant to the parallel resistance of r1&r2.
What would be a good PLC to get started out in to learn the operation and ladder programming? I would like to be able to get something cheap on ebay that I could play around with and learn about automation.
IanP, I used 9 vdc + and - for the op amp. Put a diode and a cap off of the 16vac secondary to get + and -. Ok, I can get the negative pulses to collector from the neg. diode, no prob. Neg. base signal via the op amp. And +5 to emitter BUT how do I change the voltage reference without messing...
Yes I need a gain of 1. I did use r2/r1(same resistors) but for some reason it did not work and smoked my device and 741. I need to inverse the base signal to the D.U.T. so that I can test pnp's on this curve tracer. Is pin 3 of the op amp voltage gnd for the + and - voltages? Not sure what...
I need to invert a pulse signal. I tried using a 741 op amp, I connected + and - to Vc+ and Vc-, ground to non-invert pin, original sig to invert pin, output on pin 6. It inverted to negative BUT the signal is not pulsed inverted. Where did I go wrong or do I need to add components?
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