simple DIY voltage monitor

[harp]

I am designing a simple circuit that can catch a narrow glitch in voltage fluctation, and presented in visual/audio way, with as little as posible common type components. The circuit is done on test board and work like I wish. I post schematics here and like to hear a voice of educated electrician, hopefully to insight of some flaw or better design. Thank you

[sam_sam_sam]

Is this a cable tester or is it something more than that

If it is something else please explain what you are going to use it for and explain what you are testing for

[harp]

Yes, it can be used as cable tester, but only one wire at the time. In this case the wire must have power in it, which is done by 1.8v power led supply, connection 2-3. If the wire lose connection in a fractial of time, or generate resistance greater then threshold, it beep and the state stay logged on LED. It also can be "self monitored" at some degree, with pins 2-3 connected together with jumper.................. Ocassionally, I need to be sure that some voltage stay all the time in some margin, so the device mostly produce handy audio notifycation if is something out of spec. Target is "one options more" in troubleshooting methods in repair, but real usage and usability is jet unknown...................... It is measurement device for general purpose, use it where it needed. I just work on universal pcb arrangement as a accessible and fast option to build for everyone. I just want to see and examine by profesionals before I do that

[sam_sam_sam]

Unfortunately unless you build the device you are not going to know exactly how it will respond in the real world testing because I have found in my endeavors the true value of a device is not known until you test the hell out of it

This also true for proof of concept projects as well

[Agent24]

Similar kind of thing to this one? Latching Continuity Tester
https://www.learningelectronics.net/.../latching.html

[harp]

Yes very similar for purpose, but my latch only led channel, and extend audio pulse in two tone. Because have lack of knowledge, I run in lots of trouble when I done it on dotted pcb board. For some reason, it worked like expected on breadboard... Logic ic has hardtime to latch a npn base because of drivin led. I redesign it many time, solved one problem and faced to another. I have question to transistor placement regardless to logic ic and switch, is attached schematic technicaly correct as bare minimum?

[Agent24]

Why don't you implement the latch in the usual way?
https://analogcircuitdesign.com/sr-l...-sr-flip-flop/

[harp]

I start with that, but soon noticed that space on pcb is running out. My board is dotted universal pcb dimension 100 x 32mm for whole initial circuit in tht... so any future modification I somehow must fit into it.

[sam_sam_sam]

it

I start with that, but soon noticed that space on pcb is running out. My board is dotted universal pcb dimension 100 x 32mm for whole initial circuit in tht... so any future modification I somehow must fit into it.

this okay but you really need to test it yourself throughly before making a circuit board or that is the way I would approach it

or do a double side board where your power rails are on one side and the rest of it is on the other side

This approach will save board space for you