Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
Hi,
I've got a problem with my garden solar lamps so made a circuit diagram to help me understand what is going on before trying to repair it.
Having drawn the circuit I'm struggling to see how it works. My explanation below seems backwards ie the lights are on in the day and off at night. Can...
Let's say I connect the positive probe to pin 4 on the LM324 (the IC +ve supply) and the negative probe to pin 11 on the LM324 (the IC gnd pin).
It looks to me like the positive probe has a constantly positive dc voltage around 7V relative to earth and the negative probe will see a 240V AC...
That's an interesting point you make about C1.
In your example where the ground of the op-amp is at 300V relative to Earth and the op-amp supply pin is at 310V; the IC is happy because it has a potential difference of 10V across it. However in my circuit it appears that the LM324 supply pin is...
I'm aware of the risks and take great care! Thanks for the warning though, it is worth pointing out.
You could well be right about the value of C1, I guessed it since it is not visible on the capacitor body.
Now, I understand what you say about the positive supply rail being derived from...
Unfortunately I also stuck a screwdriver into the spinning fan breaking a blade off and it turns out that a mechanical device attached to a relay used to open the fan shutters is also broken so this repair / education project is purely educational now!
I am still curious about the neutral...
I replaced R11 with a 1k and powered up the circuit. R11 burned out immediately. I removed R11 and put my ammeter in its place. This read 0.1A and provided enough gate current to switch the triac on and the fan and lamp. So I guess the triac is OK and the fault lies with the Op Amp output?
The...
On closer inspection I think that what I thought was an LED is actually a miniature bulb. Actually it looks neither like a bulb or LED that I'm familiar with...
I assumed that the motor / fan is AC because the triac can conduct in both directions with a positive (or negative) gate current...
Sorry I was working from a later revision of the circuit, with more component values on it, when I asked that question.
I'm wondering now what is the function of the capacitor C4? Is it smoothing the inputs to U1B?
And could it be possble that the SCR is, in fact, a triac? I ask because the...
How can I roughly calculate the voltage to which C3 charges? I assumed it was something like 220/220,000 * (1/ 2.pi.50.470x10-6) which gives 7mV but my circuit simulator shows it charges to 1.3V.
Ed
Thank you.
I'm confused about a part of the operation.
Current flows through R7 and D5 producing a potential across R5 which is measured as positive at the the non-inverting input to the op-amp. When current flows in the reverse direction no current can flow through D5 which would mean there...
My bathroom extractor fan failed. I took it apart and found a burned component. I was interested to see how the circuit worked in order to spec the replacement part so I drew the circuit diagram below. Trouble is I can't figure it out and really need some help. Could you describe the operation...
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
