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I think that LTspice does not know that I used a "single-supply" opamp in my peak detector circuit that has inputs and an output that work at ground.
EDIT:
Its output should be 1.4VDC.
Hello all,
I will build this one with MC33171 today afternoon and let you know how it went. Could I get some details before that how to adjust the gain in this circuit, I think I'll just change the resistor there until I get good response with my mp3 player.
I also had plans to use two led in series per output to reduce the load on the chip, but when I tried it, the other LED stayed unlit. the ones going straight to the positive rail lit like previously, but the new ones between the chip and the old LEDs didn't lit at all. I had the LEDs correctly: chip pin > LED1- > LED1+ > LED2- > LED2+ > positive rail
Yes, I'm still using +12V. I'm sure I have the LEDs in correct way, I really just added the LED #2 between the chip and the old LED #1 in the breadboard. But still, the LED #2's won't light together with the LED #1's. The LEDs are all OK condition, I tested them separately before and after these tests.
When the source has a low impedance, the gain of the inverting opamp is simply the ratio of R8/R9. Since the input coupling capacitor C4 is in series with R9 then the low cutoff frequency is determined by "one over two pi RC" as shown here:Could I get some details before that how to adjust the gain in this circuit, I think I'll just change the resistor there until I get good response with my mp3 player.
The picture in the datasheet got me thinking, but I can be just plain wrong here. If you look at the picture You'll see what I mean.
Oh right, there's two R4's there.
The R4 going from MC33171 #7 to the ground is the real R4, it should be 4.7k.
The 'fake' R4 going from LM3915 pin#5 to the transistor E is actually R5, which should and is 100k.
Yes.Could it be that the MC33171 pins are wrong in the picture?
Yes.
You copied my "preamp and peak detector" circuit from post #89. It clearly shows an MC33172 8-pins dual opamp.
When using an MC33171 single opamp then you must use its different pins.
Breadboards are a tangled nightmare of crossed and diagonal wires and parts. I use stripboard where the layout is neat and tidy and parts are soldered so nothing is intermittent.
Hello again, everyone.
I think my LED problem is related to breadboard again. There's something odd about how it works or I'm not doing something right. I've made a picture of two setups with LEDs, A and B.
A works like it should, LED lits up.
B doesn't work, LED stays unlit. In addition, if I remove the last jumper wire going from resistor to the ground, LED flashes briefly and burns up.
What I'm not seeing here? EDIT: PLENTY. SHORT CIRCUITS GALORE.