/r/electronic_circuits

Photograph via snooOG

A subreddit for all things related to component-level electronic circuits.

Component-level electronic circuits, diagrams, tutorials, design, and questions.

/r/electronic_circuits

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1

How would I make this? (To do list with lights)

I want to make a to do list, with toggle switches and led lights which respond to those switches - so you toggle a switch and a light bings when you complete a task.

I know / instead of working on my to do list, I'm working on building a to do list! But it looks fun and satisfying.

I know there are kids kits with just one light and corcuit in, but I'm thinking there might be a better way that just buying 10 or those.

I feel relatively confident in being able to get the woood work side of things down.

It wouldn't fixed to mains because I lack the competency to do that safely and responsibily..

Any tips very gratefully received!

https://preview.redd.it/kb20djoje9ae1.jpg?width=1080&format=pjpg&auto=webp&s=53891eecf364b662ee88ab16e1ab8b04f0cb2f55

1 Comment
2024/12/31
22:16 UTC

2

How to connect control pins for these ADCs for reading from external sensors in a range of 0-5volts in parallel connection (2 ADCs) in DAISY configuration?

Original post: https://www.reddit.com/r/KiCad/s/fK6dUs8yIn

Basically I have two of these chips connected in parallel (in DAISY configuration). I want to set the reference voltage to 5 volts to make measurements between 0-5 volts.

picture of schematic

0 Comments
2024/12/30
23:08 UTC

2

Button matrix encoding

Im losing my mind on this.
This is an old one sided pcb for a button matrix that i need to move to an MCU.
Since its one sided they broke the matrix and ive starred myself blind on it.

How can i get this working with matrix scanning?(or another technique)
Col2 / Col3
Row1 through 4
is easy enough, so is pin 13.
its the missing col1 thats messing with me.

Its probably easy as cake, but it just wont work for me.
help?

https://preview.redd.it/733qw3x0p0ae1.jpg?width=1536&format=pjpg&auto=webp&s=c4e0f345e2052d5b7090694c25c0e0d3c4bbed00

https://preview.redd.it/ck0p0xl1p0ae1.png?width=1124&format=png&auto=webp&s=5b74c996e71736664257fb65cc1267d094af0814

5 Comments
2024/12/30
17:02 UTC

8

Dual LED diode question

Have a dual led on this board that is red and blue. Red stays solid and blue flashes to make purple when in a pairing mode. In theory could I desolder the positive leg of the blue and bridge it with red to keep them both solid so it is always purple? Would there be a power issue with that?

4 Comments
2024/12/28
20:17 UTC

1

Help with creating AM Radio?

I have tried creating several AM Radio circuits, but they have all failed to produce any noise other than a single click when being fed power. I am specifically looking for a circuit which utilizes the 2N2222 transistor or similar. If someone could comment a schematic or help lead me in the right direction, that would be great. Thanks in advance.

1 Comment
2024/12/26
06:20 UTC

7

Can I connect a motion sensor with a doorbell?

Hi, i have the following:

Motion Sensor:
- Steren ALA-034

Wireless Doorbell Chime:
- Doorbell WL-3A-A
- Magnetic Sensor WLTX-205-A

I added some cables to the speaker connections of the motion sensor that extend for 10 meters, and I added a small extra speaker.

Now I need to add another speaker further away, so I bought a Wireless Doorbell. The problem is that plans changed, and now the door is going to stay open, so the sensor will work, but the Doorbell, being magnetic, won’t work.

The question:
I’d like to know if I can combine the sensor with the wireless magnetic "transmitter" so I can turn on and off the piece that handles the magnetic contact.

Important: I don’t know much about electronics, but I have some knowledge. It’s really hard to find this kind of accessories here, so buying one, at least for now, can’t happen; this is to avoid comments about it.

https://preview.redd.it/ha4ctsf3s39e1.png?width=8503&format=png&auto=webp&s=e6d2b62c88946efbc09bdad639cdd1ec9a9ac3e9

The two pins and the button that are only inside the magnetic transmitter activate the bell.

0 Comments
2024/12/26
02:33 UTC

16

Can you help with the identification of the connection of each transistor? I know T1 and T2 make up a differential amplifier, but I don't know about the others. My take is that T3 and T4 are common emitter, but I'm not completely sure. Also, are T7 and T8 Darlington or Sziklai transistors?

4 Comments
2024/12/22
17:32 UTC

27

This is the diagram made to represent a saw I have. Why is the "transformer" plugged "wrong"?

The grid electricity arrives, phase passes through a switch while the neuter goes directly to the "transformer".

The false transformer is built like a real one, an ironed ring with two coils. In this case of the same number of spirals. The weird thing is that the primary coil is not connected to phase and neuter but rather is in series with the condensator and the motor.

Im sure it's just another component which I just dont know of. Thanks for everything :D.

22 Comments
2024/12/19
11:02 UTC

4

What is this Component?

Someone from the staff plugged 220V AC instead of 12V DC into our attendance machine by mistake. Repair shops in my city returned the machine saying it can not be repaired. What could be the marked component?

It was the only thing that looked burnt when I opened the machine. It was all black.
The machine has a lot of attendance data.

Suggestions on how to repair it and what other things could also be damaged.

https://preview.redd.it/gwn4ew8mem7e1.jpg?width=1729&format=pjpg&auto=webp&s=fecf708f2f44eb4ea181137d6b1bfd20260565fe

9 Comments
2024/12/18
14:52 UTC

0

How can I edit this frequency meter schematic to include these parts?

Hey! So I had a post a while ago that I deleted asking for some help, I'm not back with a little bit of some of my work. I have this

https://preview.redd.it/40817gx76a7e1.png?width=747&format=png&auto=webp&s=5d36df323902dcdf6598f94fc8a96716a11a798e

final schematic that our prof gave us, and we need to edit it by removing/substituting stuff in this with these:

  1. Control logic schematic

https://preview.redd.it/0mu7l77f7a7e1.png?width=856&format=png&auto=webp&s=3290ebb3266931ffc162f0ef39badb3e3ac33020

  1. Autoscaling logic schematic

https://preview.redd.it/u80zt0oi7a7e1.png?width=908&format=png&auto=webp&s=b29b606aa893ee0196b9070fd11f332359b79498

  1. Sequencer schematic

https://preview.redd.it/2mk5qp3l7a7e1.png?width=937&format=png&auto=webp&s=ce6c36df3d60594b99faa4f18f3e39a994d8f6d9

We need to follow this hand drawn schematic he gave us. If someone is able to help let me know.

Translations are word for word:

-Baza de timp -> Time base
-TMS -> Selected measure time
-Logica de autoscalare -> Autoscaling logic
- Logica de control -> Control logic or sequencer
- Reg. de memorie -> Memory register
-Bloc afisare dinamica -> Dynamic display block

https://preview.redd.it/294f049w6a7e1.png?width=1526&format=png&auto=webp&s=b2c0627364bfa7376f0b3a5c9ebb8e45a1e2fc22

0 Comments
2024/12/16
21:51 UTC

5

Diode orientation and function

In this Ms paint diagram, if one wants the filament on circuit B to operate on its own when circuit B switch is closed and A open but have both A and B burn when the switch in circuit A is closed and B open, is this diode spliced in able to make that happen and is the orientation of the diode correct?

3 Comments
2024/12/16
14:46 UTC

2

Finding the usage of board

This was sent by a friend of mine, he wanted to know the details of the board and its usage. I also didn't know it can anyone help with it!?

1 Comment
2024/12/16
08:35 UTC

1

Alguien sabe como puedo arreglarlo, no se escucha del otro lado y se safaron esos tres cablecitos);

2 Comments
2024/12/15
20:50 UTC

0

Electronic Companat

Baby toy-Hh707k-2.4g 12v 7pin motherboard. Damage component number name

1 Comment
2024/12/15
21:20 UTC

1

Control 7 different protoboards by 1 SPST DIP x4

The second image is how i try it but idk if it run like tinkercad in real life and i'm afraid they'll burn, please help me with any suggestion

2 Comments
2024/12/15
19:13 UTC

2

On/off switch to one pulse

Anyone knows how to convert on/off light switch into button (one pulse signal)?

7 Comments
2024/12/14
08:14 UTC

4

On a blank through hole board, why do people not simply run a continuous bead around the perimeter of the board as a ground rail?

Hi community.

So in my collage days I would take tons of Adderall during that time I decided to teach myself to solder etc, built valve powered guitar pedal, modified stuff.

Im 36 now, trying to get back into it and customize a cheap condenser mic and upgrade it.
https://www.instructables.com/Modify-a-cheap-LDC-Condenser-microphone/

On a blank through hole board, why do people not simply run a continuous bead around the perimeter of the board as a ground rail? Intuitively it seems like the most convenient thing to do.

What is the proper way of connecting ground to the rest of the circuit?
In schematics the rest of the process is evident as long as you know how to download data sheets, but the grounding part seems to escape me.

Thanks

14 Comments
2024/12/13
14:03 UTC

9

multi voltage power supply

5 Comments
2024/12/13
00:59 UTC

1

FM Radio Wiring Query - Creative Zen Z500 Docking Station

Hi, I'm looking for help on fixing a 75 ohm radio antenna that only produces static.

Background / Problem:

  • I recently got a Creative Z500 (aka MF8047) docking station for a Zen Vision M music player.
  • This dock has an F-type connector on the back which is connected to a telescopic aerial (see photo). This aerial is then wired internally to the Zen Vision M which can use it to play FM radio.
  • The Zen Vision M detects an aerial has been attached, but I only receive static, i.e., no signal is coming through.

Wiring:

  • Internally, there are 2 wires soldered as follows:
  • Wire 1: It is soldered from the Zen Vision M to the back of the F-type socket that the aerial is attached to. The same wire then goes into a black device (possibly a resistor to bring it down to 75 ohms - see left of attached photo). There is another cable coming from this black device to the grounding point above the coax socket.
  • Wire 2: It is soldered from the Zen Vision M directly to the grounding point above the coax socket. I understand it is the ground?

Query:

  • Do you think the FM aerial has been wired correctly? I'm wondering if both wires should be connected to the grounding point given I'm only receiving static.

Note:

  • I was able to test the FM radio on my Zen Vision M with a set of headphones (which is an alternative way of adding an aerial), and it worked perfectly.

Internal Wiring 1

Internal Wiring 2

Rear - Telescopic Aerial

0 Comments
2024/12/12
22:33 UTC

2

Why my amplifier sound bad

Hello, recently I challenged myself to build a class A amplifier, I created a small spreadsheet to determine the values of the components I was going to use, then pass the test time I realize that there is a lot of parasitic noise and that there is no bass, I thought it came from my breadboard but even on a solder wafer the same problems occur, Will you know where my problem can come from, here is my calculation sheet, the diagram and a photo of my amplifier prototype. I use a 5V USB power supply and the signal comes from my phone.

Here are my specifications:

IC = 10mA

HFE = 100

VCC = 5V

VCE = /2 of VCC = 2,5V

VE = 20% of VCC = 1V

VB = VE + VBE = 1,7V

VBE = 0,7V

fc = 20hz

R_Headphone = 32ohm

VRE = IC x RE = 0,1mA

the formulas used:

for IC = 10mA

IB = IC / HFE

RE = VE / IC

RC = VCC - VCE / IC

C_signal = 1 / 2pi x fc x R2

C_HP = 1 / 2pi x fc x R_HP

C_RE = 1 / 2pi x fc x RE

R1 = VCC - VBE - VRE / 10xIB

R2 = VBE + VRE / 10xIB

and the result:

RC = 250

RE = 100

R1 = 5k

R2 = 2.5k

C_Signal = 3uf

C_RE = 79.6uf

C_HP = 248uf

the schematic:

https://preview.redd.it/yodrxinq8g6e1.png?width=911&format=png&auto=webp&s=97dca98e35687e90a71be5e467eae6fa7509938b

and my prototype:
I didn't have any space so I wired it in mono :P

https://preview.redd.it/5j8naqt89g6e1.jpg?width=3468&format=pjpg&auto=webp&s=ab4a0737f81597cf202ea96879d8885e152759d2

and it works but with very little bass and a lot of noise

5 Comments
2024/12/12
17:13 UTC

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