If you do not have a scope here is a low speed freebee -
You can start with a PC sound card based scope for free. Will give you basically
audio range scope, spectrum analyzer, and function generator all using your
PC sound card. It may not be fast enough to handle the character LCD interface
however.
https://www.zeitnitz.eu/scope_en
http://www.zelscope.com/
http://www.ledametrix.com/oscope/
http://www.virtins.com/downloads.shtml
But first build a simple circuit to protect sound card inputs so you do not
ruin from transients, overvoltage. Google "protect sound card input".
For example http://makezine.com/projects/sound-card-oscilloscope/
A real inexpensive Logic Analyzer/pc combo can be had with this -
https://www.ebay.com/itm/USB-Logic-...h=item33f2ef28ec:g:NNoAAOSwjXVaoiyH:rk:4f:0
There are many vendors of this on ebay.
You download and install Saleae software to run it. https://www.saleae.com/downloads/
Sound card impedance bridge -
http://www.marucchi.it/ZRLC_web/ZRLC/Steber_An_LMS_Impedance_Bridge.pdf
http://www.sillanumsoft.org/ZRLC.htm
Regards, Dana.
But first build a simple circuit to protect sound card inputs so you do not
ruin from transients, overvoltage. Google "protect sound card input".
For example http://makezine.com/projects/sound-card-oscilloscope/
Yes.And does the cheap logic analyzer actually work with the saleae software?
No need to be sorry.Sorry but I would rather just buy a cheap USB scope.
I am afraid to use the sound card, I don't want to lose my HP laptop. The USB scope on ebay for $27 sounds promising. Is there an installation disk for software? If so, what kind?Of course you risk frying your sound card so bear that in mind before taking this advice.
The better advice is to buy a cheap USB scope. There are many on eBay and other places.
Here is a nice standalone one for only $27 US
https://www.ebay.com/itm/DSO150-2-4-LCD-Digital-Display-Oscilloscope-Assembled-Case-Test-Clip-Pack-New/192807997631?_trkparms=aid=555018&algo=PL.SIM&ao=1&asc=55992&meid=1d612bf5cf3a4e6fa743ff0a004e34eb&pid=100005&rk=4&rkt=12&sd=263783701694&itm=192807997631&_trksid=p2047675.c100005.m1851
Here is a name brand one for a bit more but requires a PC.
https://www.ebay.com/itm/New-Useful...530143?hash=item3fa7c33e1f:g:qDwAAOSw1opba-9f
Another cheap one:
https://www.ebay.com/itm/77CE-Assem...f4:m:m8nNY-e0SFLE8J9flyEWTOw&var=553166751305
I don't know of a current limiter in CM1, the clock is powered with a 1.5v cell. I am using the 2n7000 because a BJT output was 4.3v only (I need 5v) as an emitter follower. My logic probe indicates that hi and lo levels are fine with the schematic circuit I provided.I designed digital circuits for many years with a voltmeter and a logic probe. For clocks, you just need a frequency divider to make it slow enough to see with a visual indicator.
Why are you using a BJT and a MOSFET? One or the other should be sufficient.
Is there a current limiter in CM1?
EDIT: To answer your question, it can drive TTL, but you should decrease the voltage to 5V.
I think that $27 is a stand alone. But I would consider spending a bit more and getting the Hantek. It would make it a lot easier for you to share wave forms on the forum.I am afraid to use the sound card, I don't want to lose my HP laptop. The USB scope on ebay for $27 sounds promising. Is there an installation disk for software? If so, what kind?
When the transistor is off, the output should be supply voltage. It's the load that's causing the voltage to drop.I don't know of a current limiter in CM1, the clock is powered with a 1.5v cell. I am using the 2n7000 because a BJT output was 4.3v only (I need 5v) as an emitter follower.
It's working okay with the output from the drain of the FET, I'll leave it the way it is. I just have to put the circuit board in a box now. My 4"x6"x3" abs plastic box cost me $10 on eBay. Is there a cheaper source, especially for bigger boxes.When the transistor is off, the output should be supply voltage. It's the load that's causing the voltage to drop.
Replace D3 and D4 with 1k resistors, change R4 to 1k. and take the output from the collector of the BJT. High level output voltage should be 5.25V.
I'd try aliexpress.com. Here's a 200mmX120mmX75mm box for $8 (on sale).My 4"x6"x3" abs plastic box cost me $10 on eBay. Is there a cheaper source, especially for bigger boxes.
Looks good and free shipping. It looks like it's not transparent but it says it's clear and wiring would show through. We need to hide wires so people wouldn't think it's dangerous.I'd try aliexpress.com. Here's a 200mmX120mmX75mm box for $8 (on sale).
Free shipping may not last because the current Administration is in a trade war with China.Looks good and free shipping. It looks like it's not transparent but it says it's clear and wiring would show through. We need to hide wires so people wouldn't think it's dangerous.
Of course you risk frying your sound card so bear that in mind before taking this advice.
The better advice is to buy a cheap USB scope. There are many on eBay and other places.
Here is a nice standalone one for only $27 US
https://www.ebay.com/itm/DSO150-2-4-LCD-Digital-Display-Oscilloscope-Assembled-Case-Test-Clip-Pack-New/192807997631?_trkparms=aid=555018&algo=PL.SIM&ao=1&asc=55992&meid=1d612bf5cf3a4e6fa743ff0a004e34eb&pid=100005&rk=4&rkt=12&sd=263783701694&itm=192807997631&_trksid=p2047675.c100005.m1851
Here is a name brand one for a bit more but requires a PC.
https://www.ebay.com/itm/New-Useful...530143?hash=item3fa7c33e1f:g:qDwAAOSw1opba-9f
Another cheap one:
https://www.ebay.com/itm/77CE-Assem...f4:m:m8nNY-e0SFLE8J9flyEWTOw&var=553166751305
Free shipping may not last because the current Administration is in a trade war with China.
Lead times are listed as 30 days or more. I've found that they're conservative in their ETA's. That particular box is only on sale for a few more hours. After that, it's closer to the $10 you paid on eBay. Chinese sellers also list on eBay.
I don't think the Hantek 6022BE is for windows 8 operating system. I am running Windows 8.1 on my HP laptop. Am I wrong?Of course you risk frying your sound card so bear that in mind before taking this advice.
The better advice is to buy a cheap USB scope. There are many on eBay and other places.
Here is a nice standalone one for only $27 US
https://www.ebay.com/itm/DSO150-2-4-LCD-Digital-Display-Oscilloscope-Assembled-Case-Test-Clip-Pack-New/192807997631?_trkparms=aid=555018&algo=PL.SIM&ao=1&asc=55992&meid=1d612bf5cf3a4e6fa743ff0a004e34eb&pid=100005&rk=4&rkt=12&sd=263783701694&itm=192807997631&_trksid=p2047675.c100005.m1851
Here is a name brand one for a bit more but requires a PC.
https://www.ebay.com/itm/New-Useful...530143?hash=item3fa7c33e1f:g:qDwAAOSw1opba-9f
Another cheap one:
https://www.ebay.com/itm/77CE-Assem...f4:m:m8nNY-e0SFLE8J9flyEWTOw&var=553166751305
Thank you, I feel better now.To the question in the OP, yes the output should get very close to ground. I should able to clock TTL but the 1k + LED load may give you trouble getting an output voltage that is a reliable high state for CMOS or TTL. I suggest buffering the LED.