# All Questions

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### Discrepancy in theoretical vs measured gainbandwidth in LTSPICE ideal OTA

I am using a very simple model to show the unity gainbandwidth of a closed loop sample and hold with a closed loop gain of 2. One would expect an ideal OTA to have a GBW independent of rout as GBW is ...
• 1,672
6 views

### Implementing A/D conversion circuit to a DIY clamp meter

I was looking for cheap clamp meter projects and found this one: DC non invasive current clamp for oscilloscope DIY. After reading about this project, I noticed that it had a BNC output to read values ...
• 35
10 views

### How can I generate a sawtooth waveform?

I am trying to generate a sawtooth waveform with either an integrated circuit or by building my own circuit. I need to be able to vary the frequency.
• 601
10 views

### How are S-Parameters and Reactance related, can one be calculated from the other?

I know that, for example, $X_L=2\pi f L$ will calculate reactance of an ideal inductor, but can this be calculated for a real component model? Given the S-Parameter values at some frequency from an ...
• 774
1 vote
22 views

### Resistive Moisture Sensors, What is the purpose of the 2N3904 Transistor in the Sparkfun Circuit?

the two circuits below do the same things as far as I can tell, they both measure soil moisture using resistive sensing. However the one from Sparkfun is using a 2N3904 transistor, since the voltage ...
21 views

### Power/Sense line connections when a relay in path

I need to connect a power supply instrument with (power and sense line) to my IC, this IC is separated by a relay. Can I connect/tie the sense line of the instrument close to IC in the layout (as ...
43 views

### Smoothing potentiometer output

I am building a paddle controller for my Commodore C64. Basically all you need is a 470k (or 500k) potentiometer connected to two of the joystick wires. Internally, the C64 has capacitors through ...
• 101
50 views

### Integrator circuit - no DC path from output to input

Someone told me that this circuit does not work unless there is DC bias path in the feedback. Because the op-amp is operating open loop for DC. Someone also told me that the input transistor pair of ...
26 views

### Samlex power inverter PCB wiring schematic or test points

I am trying to find a wiring diagram or voltage test points for a Samlex 1500 watt PST150S-12A inverter board. Losing a/c output, have found a possible short on board. 2 of the 8 output mosfets have ...
29 views

• 301
100 views

### Need 64Hz square wave green LED driver for a mosquito zapper

I have several 10 watt COB (Chip-on-Board) green LEDs which apparently are the best color to attract mosquitoes if driven at an ideal pulsing square wave frequency of 64 Hz. I was going to use a ...
1 vote
38 views

### VHDL: How to use records as PORTS with IN and OUT parameters?

Is there a syntax where one can use a record type in a PORT declaration, but specify that certain members of the record are IN ...
49 views

### Why does this solid state relay circuit work sometimes and not other times? (stuck closed)

It's a very simple open collector output from one device driving a solid-state relay (VO1400) in another device. You can see the power transistors (BS868) that drive OUTn.n in the circuit diagram. ...
43 views

### 5V protection circuits

For my project, I'm using this solar shield in order to use some solar panels and a battery to power my Arduino. In order to protect the solar shield (where the maximum solar input is 6V) I would ...
• 109
38 views

### HDMI: Can a computer still detect a monitor properly if some of the TDMS pins/wires are damaged? [closed]

Can a faulty HDMI-cable with damaged TDMS pins/wires still work to the extent that the computer can still detect the monitor, but the monitor just will not display anything (except for no signal)?
• 101
30 views

### How to correctly terminate a TTL line between two ICs?

I am designing a circuit to convert a 5ns ECL signal to an LVTTL signal of >10ns. The SY100ELT25 is used to convert the ECL to 5V TTL which is then fed into the SN74LVC1G123 to further reduce the ...
26 views

### Clap sensor Proteus simulation issue

I've been trying to connect an electret microphone into this circuit, although none of the imported electret microphones work. The circuit is designed to keep the LED open for about 1 second by the ...
43 views

### Maximize the voltage gain of the CE amplifier [duplicate]

I have a problem in maximizing the voltage gain in given CE amplifier. The problem is to determine the values of R2 and R3. What is the process of getting the values of R2 and R3?
41 views

### Construct a 16x8 memory [closed]

I am very new to this and have no idea how to proceed, I have looked at tutorials. Someone help me. : ) I have to design and simulate a 16x8 memory on logisim.
40 views

### In this circuit, the light intensity sensor (LDR) only senses 3_2 cm. How can I improve the sensitivity of this sensor to reach 1m?

In this circuit, the light intensity sensor (LDR) only senses 3_2 cm. How can I improve the sensitivity of this sensor to reach 1m? https://ibb.co/c3X1NRS
41 views

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1 vote
24 views

### How to properly handle mixed RF/digital design in HFSS 3Dlayout

I have a big design imported from Altium into HFSS 3DLayout with several RFIC that I want to simulate. RF and Digital (SPI) nets are included in this design. I'm interested mainly in the RF side of ...
44 views

### Which are better and more accurate alternatives to LMV324 by Texas Instruments? [closed]

I need LMV324 form my electronics circuit, but it is not available in India, and someone said there are more accurate quad amplifiers available than this. Can someone tell more quad amplifiers with ...
• 69
84 views

### Measuring the reflection coefficient $\Gamma$

I want to measure the reflection coefficient. I have the following circuit: With these measurements I get the following graphs: Is the reflection coefficient the negative peak of the RED signal ...
• 187
31 views

### Alkaline vs lithium vs other battery for specific use [closed]

I would like to know which type of battery would be better for a device with the following specifications: Bluetooth access system control (BLE) Device will have a low duty cycle, being most of the ...
• 143
29 views

### Why is the change in reactive power not equal to the line reactance drop?

I am working on an equivalent network of a two bus system right now. I know the $P$, $Q$ and power factor at Bus 2. Bus 1 is taken as a slack bus ($V = 1 PU$, $\delta$ = 0). Using iterative ...
• 101
63 views

### What will be the new value of Vy? [closed]

It is clear to me that Vx will charge upto 3.4V and Vy will also be 3.4V but what will be the value of Vy if I increase the gate voltage of second MOS to (say) 4.2V? Also, if possible kindly attach ...
1 vote
47 views

### Mitigating FET current spikes in an SMPS buck converter

I'm currently designing an SMPS buck converter that converts 311VDC to 60VDC at 10 Amps maximum load. I'm using ESP32 for the PWM control, and IR2110 for the switching driver. The switch I'm currently ...
• 111
68 views

### Is there a manufacturer that produces an analog ohmmeter specifically for [closed]

Does anyone know of a manufacturer that produces a specific type of analog ohmmeter for testing the automotive relays equipped with silicon diodes ? I have heard that it is a newer type and has an ...
1 vote
53 views

### Identify number of strings in Philips 14.5W LED PCB

Is it possible by just looking at the attached image whether the LEDs are in a single series circuit, or whether they're configured in series/parallel? The image is not great but I tried to highlight ...
• 113
229 views

### How to find a fast optocoupler (or how to read the datasheet)

I am looking for an optocoupler that can sustain a 400kHz signal. Now the question is how can I find out from a datasheet whether it does? Looking at a typical PC817 datasheet I see the following ...
• 151
25 views

### Singular Value Decomposition MIMO

Singular Value Decomposition in MIMO Spatial Multiplexing requires knowledge of the channel state information at both the transmit and the receive and allows parallel independent data streams to be ...
• 341
29 views

### I need help on circuit of 28v DC with 6 amp flow + superimposed higher volts of small wattage, so as 100v present with amps from first source [closed]

I need help to redo my circuit of 28v DC with 6 amp flow out, from DC converter, and hooking in Parallel, with with superimposed small 30 watt module, as 100volts DC so as the small end electrodes ...
• 1
59 views

### Different power supplies

I have an the following components: Arduino Mega (9V) 8 relays (5V) 4 AC/DC voltage sensors (5V) SIM800L (4.1 V) How many power supplies do I need on my circuit board? Is it good idea to use one ...
• 111
50 views

### Grounding sensors to large bodies

I've attached a diagram of what I'm talking about. I have a large (600x300x10 mm) aluminum block in which I place thermistors to monitor the temperature distribution in the plate (in a standard ...
58 views

### How to distinguish which buttons have fixed on/off positions similar to a flashlight button?

I'm searching for a button/switch similar to one on a common flashlight: you click the button to turn the light on, then eventually click it again to turn off. Example clip of Button (Adafruit / ...
• 115
19 views

### Solar panel to power load first charger second [closed]

I have small cold frames ventilated w/ a muffin fan powered by my panel through a buck/boost board to a temp controller board. I want to power a charge controller when the temp controller is not ...
39 views

### Running 400 Hz, 380 V spindle motor on 220 V, 3-phase VFD

I just (mistakenly) purchased a 380 V (400 Hz) spindle motor and I have a 220 V, 3-phase VFD. The manufacturer said the winding is a special configuration that performs equally well with either ...
10 views

### LoRa spreading factor

How can I calculate the spreading factor for Semtech SX1261 transceiver? And how Spreading factor is related to LoRa modem setting along with Bandwidth and Code Rate?
1 vote
37 views

### Why my ESP32-CAM won't power up with 5 volts?

I'm new into electronics and I decided to power up my ESP32-CAM with a 9V battery instead FTDI programmer (I measured it, it gives 5V to ESP32-CAM). I thought if I reduce voltage to 5V with mini ...
• 11