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problem in SPICE

Adding in R20 is to protect Q1 from overvoltage from the CCL (3K). I properly see little gain loss up to 800 ohms. But at 900 ohms, =*paff*= major decrease. And i do not see any other large change. WTH?

Version 4 SHEET 1 1012 680 WIRE 672 -128 224 -128 WIRE 224 -80 224 -128 WIRE 672 -80 672 -128 WIRE 16 16 16 -32 WIRE 16 16 -48 16 WIRE 224 16 224 0 WIRE 224 16 16 16 WIRE 256 16 224 16 WIRE 256 80 256 16 WIRE 672 80 672 0 WIRE 16 112 16 16 WIRE -48 320 -48 16 WIRE 256 320 256 160 WIRE 256 320 224 320 WIRE 16 368 16 192 WIRE 48 368 16 368 WIRE 160 368 128 368 WIRE 16 384 16 368 WIRE 224 448 224 416 WIRE -416 464 -480 464 WIRE -304 464 -336 464 WIRE -272 464 -304 464 WIRE -176 464 -192 464 WIRE -48 464 -48 384 WIRE -48 464 -96 464 WIRE 16 480 16 464 WIRE -304 496 -304 464 WIRE -64 528 -160 528 WIRE -48 528 -48 464 WIRE -48 528 -64 528 WIRE -64 544 -64 528 WIRE -304 608 -304 576 WIRE -160 608 -304 608 WIRE -64 608 -160 608 WIRE 16 608 16 576 WIRE 16 608 -64 608 WIRE 224 608 224 528 WIRE 224 608 16 608 WIRE 16 656 16 608 FLAG 672 80 0 FLAG 16 656 0 FLAG 16 -32 out FLAG -480 464 VIN IOPIN -480 464 In SYMBOL npn 160 320 R0 SYMATTR InstName Q2 SYMATTR Value 2N3904 SYMBOL res 208 432 R0 SYMATTR InstName R4 SYMATTR Value 0.001 SYMBOL res 0 96 R0 SYMATTR InstName R2 SYMATTR Value 50K SYMBOL res -176 448 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R3 SYMATTR Value 3.0K SYMBOL res 208 -96 R0 SYMATTR InstName R1 SYMATTR Value 6.8K SYMBOL voltage 672 -96 R0 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName Vline SYMATTR Value 120V SYMBOL res -320 480 R0 WINDOW 0 -37 60 Left 2 WINDOW 3 35 80 Left 2 SYMATTR InstName R8 SYMATTR Value 1.0 SYMBOL res -320 448 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R9 SYMATTR Value 1.0K SYMBOL pnp -48 576 M180 SYMATTR InstName Q1 SYMATTR Value 2N3906 SYMBOL cap -64 320 R0 WINDOW 3 -64 2 Left 2

SYMATTR InstName C1 SYMBOL res 144 352 R90 WINDOW 0 -38 63 VBottom 2 WINDOW 3 -34 61 VTop 2 SYMATTR InstName R6 SYMATTR Value 0.001 SYMBOL res 0 368 R0 WINDOW 0 31 44 Left 2 SYMATTR InstName R7 SYMATTR Value 48 SYMBOL res 240 64 R0 SYMATTR InstName R5 SYMATTR Value 5.1K SYMBOL diode -80 544 R0 WINDOW 0 39 33 Left 2 WINDOW 3 -18 94 Left 2 SYMATTR InstName D1 SYMATTR Value 1N4148 SYMBOL res -80 448 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R10 SYMATTR Value 800 SYMBOL res -176 512 R0 SYMATTR InstName R11 SYMATTR Value 1Meg TEXT -512 240 Left 2 !V1 VIN 0 AC 1 SIN(0 0.001 1000KHZ) TEXT -408 200 Left 2 !.ac oct 5 0.01Hz 1000Khz TEXT 104 -8 Left 2 ;Vo=50V TEXT 304 -48 Left 2 ;Ic=10mA TEXT 80 136 Left 2 ;980uA TEXT 88 424 Left 2 ;Ib=30uA TEXT -344 432 Left 2 ;-60dB TEXT 80 40 Left 2 ;-9dB TEXT 24 480 Left 2 ;Ie=956uA TEXT 32 576 Left 2 ;Ib=5uA TEXT 240 424 Left 2 ;9.3mA TEXT -288 64 Left 2 !.TEMP 27 TEXT 120 312 Left 2 ;Vc=1.3V TEXT -408 136 Left 2 ;Commented values are at 27C\nunless otherwise stated TEXT 280 184 Left 2 ;For about 26mW Q2 TEXT -424 400 Left 2 ;R3 emulates the CCL TEXT 48 72 Left 2 ;-21dB@187C TEXT 272 304 Left 2 ;Vc=6.7V@18C TEXT 320 424 Left 2 ;8.9mA@187C TEXT 280 216 Left 2 ;60mW@187C (ouch!) TEXT -536 360 Left 2 ;NOTE: R10 at 900 ohms is a disaster for gain

Reply to
Robert Baer
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Change V1 to a fixed (say) 10Hz 1V sine and run a transient simulation with a stop time of 1 sec. You'll soon see the problem as you change R10. Also, you don't need the 1mR resistors to measure current - LTspice does that for you by turning the voltage probe to a current clamp if you point to a circuit node, eg an emitter arrow.

This is a crap CCL circuit. Yes, I know it's not yours.

Cheers

--
Syd
Reply to
Syd Rumpo

What in the world? What's it supposed to perform?

[snip] Full listing at Message-ID:

...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

It s getting a bit late here (1AM) so should go to bed after a long day. I interpret your "use fixed frequency" response as a hint to see major distortion - prolly to to saturation of Q1. Actually, i should confess, it is a circuit i designed about 10 years ago and tweaked towards some other person's suggestions. Original worked nicely.

As a matter of curiosity, what would you suggest for a CCL circuit (that did not need a large cap)?

Reply to
Robert Baer

It is an amplifier that takes small pulses from a collar locator (2 magnets N-N inside a coil) and amplifies them; with an adjustable roll-off in the 100Hz region. Used in the oil patch to find where one pipe ends and the other begins (when connected).

Reply to
Robert Baer

Describe signal in, and desired signal out? ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

Jim Thompson wrote:

"Signal" in: the CCL travels down the middle of a pipe of many sections screed together; as the CCL passes by a connection, its coil generates a short pulse perhaps in the region of a few millivolts in amplitude. Signal out could be said to be in the region of 40dB higher, depending on load, supply voltage, and temperature of the electronics (rough region 25C to 190C). Original CCL reference circuit is: Version 4 SHEET 1 1012 680 WIRE 672 -128 224 -128 WIRE 224 -80 224 -128 WIRE 672 -80 672 -128 WIRE 64 16 64 -32 WIRE 224 16 224 0 WIRE 224 16 64 16 WIRE 256 16 224 16 WIRE 64 64 64 16 WIRE 672 80 672 0 WIRE 64 160 64 144 WIRE 192 160 64 160 WIRE 64 176 64 160 WIRE 192 176 192 160 WIRE 192 272 192 240 WIRE 416 272 368 272 WIRE 512 272 416 272 WIRE 512 304 512 272 WIRE 256 320 256 16 WIRE 256 320 224 320 WIRE 416 352 416 272 WIRE 448 352 416 352 WIRE 64 368 64 256 WIRE 80 368 64 368 WIRE 512 416 512 400 WIRE 512 416 416 416 WIRE 512 432 512 416 WIRE 368 448 368 272 WIRE -416 464 -480 464 WIRE -304 464 -336 464 WIRE -96 464 -304 464 WIRE 64 464 64 368 WIRE 64 464 -16 464 WIRE 416 480 416 416 WIRE 448 480 416 480 WIRE -304 496 -304 464 WIRE 224 496 224 416 WIRE -304 608 -304 576 WIRE 16 608 -304 608 WIRE 224 608 224 576 WIRE 224 608 16 608 WIRE 512 608 512 528 WIRE 512 608 224 608 WIRE 16 656 16 608 FLAG 672 80 0 FLAG 16 656 0 FLAG 64 -32 out FLAG -480 464 VIN IOPIN -480 464 In FLAG 192 272 0 SYMBOL npn 160 320 R0 SYMATTR InstName Q1 SYMATTR Value QN2102 SYMBOL res 208 480 R0 SYMATTR InstName R4 SYMATTR Value 0.001 SYMBOL res 48 48 R0 SYMATTR InstName R2 SYMATTR Value 10K SYMBOL res 208 -96 R0 SYMATTR InstName R1 SYMATTR Value 6.8K SYMBOL voltage 672 -96 R0 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName Vline SYMATTR Value 120V SYMBOL res -320 480 R0 WINDOW 0 42 31 Left 2 WINDOW 3 35 80 Left 2 SYMATTR InstName R8 SYMATTR Value 1.0 SYMBOL res -320 448 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R9 SYMATTR Value 1.0K SYMBOL cap 176 176 R0 WINDOW 3 -16 -45 Left 2

SYMATTR InstName C1 SYMBOL res 0 448 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R5 SYMATTR Value 3K SYMBOL res 48 160 R0 SYMATTR InstName R3 SYMATTR Value 33K SYMBOL res 176 352 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R6 SYMATTR Value 0.001 SYMBOL npn 448 304 R0 SYMATTR InstName Q2 SYMATTR Value 2N2222 SYMBOL npn 448 432 R0 SYMATTR InstName Q3 SYMATTR Value 2N2222 TEXT -480 384 Left 2 !V1 VIN 0 AC 1 SIN(0 0.001 1000KHZ) TEXT -464 336 Left 2 !.ac oct 5 0.01Hz 1000Khz TEXT 104 -8 Left 2 ;Vo=16V TEXT 88 424 Left 2 ;Ib=145uA TEXT -256 440 Left 2 ;-60dB TEXT 240 424 Left 2 ;15mA TEXT -424 112 Left 2 !.TEMP 27 TEXT -480 -48 Left 2 ;Commented values are at 27C TEXT -448 -96 Left 2 ;R5 emulates the CCL TEXT -560 152 Left 2 !.MODEL QN2102 NPN(\n+ IS= 9.600E-14 BF= 120. NE= 2.00 IKF= .700\n+ BR= 3.00 NC= 2.00 ISE=

4.800E-11\n+ RB= 10.0 RC= 1.40 ISC= 4.800E-11\n+ CJE= 9.000E-11 TF= 2.222E-09 CJC= 3.000E-11\n+ TR= 1.450E-05) TEXT -312 48 Left 2 ;Gain 135 with R4=0 (-17dB),\n ~100 with R4=10,\n~110 with 2 diodes (10mA) TEXT 320 232 Left 2 ;2 diodes for testing at emitter, Q1 TEXT -376 -16 Left 2 !.TEMP 27 TEXT -168 -104 Left 5 ;SIEbasic
Reply to
Robert Baer

[snip]
[snip] Complete Listing at Message-ID:

What does "R5 emulates the CCL" mean... equivalent impedance? ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

R5 is set to the typical value of the coil resistance. Nobody in the oil patch considers the inductance, because that is not a factor there.

Reply to
Robert Baer

You said ~1mV signal, yet that latest schematic attenuates 1mV down to

1uV.

And how does that high a frequency get all the way up the long cable? ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

Look more carefully, the input to the 60dB pad is 1V, driving 1mV into the CCL amp. The CCL amp is downhole with the solid-state (magnets, coil) CCL itself. It can get a bit warm...

Reply to
Robert Baer

In the .AC analysis

In the .TRAN analysis see

How does 1MHz make it up the wire? ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

I don't really understand your problem, Robert.

The first LTSpice listing was completely different from your second listing.

Please tell us your complaint and what it is you are seeking in either or both cases.

Thanks.

Reply to
John S
**sniped due to aioe limitation

Look carefully, 1V in at R9, -60dB at R8 (which is 1mV) so the simulated CCL R5 "is generating the typical 1mV signal".

Reply to
Robert Baer

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