Posts by misk94555
Can a circuit board be waterproof enough to form a wall of a waterproof enclosure? Regular PCBs made of FR-4 with solder mask is what I have in mind. But I'm not barring less common PCB materials...
Once in a while in literature I see a DC offset subtraction loop. Here are a few more examples. DC servo loop removes a DC offset after an op-amp. DC servo loop removes DC current from a photo...
Consider a device with a microSD card. The microcontroller writes to the SD card periodically. The operators have an ability to remove the microSD card at any time (they will be removing it every...
Got a question about hazardous breakpoints in real-time firmware. Does C have a mechanism which lets me mark a section of code such that breakpoints are somehow ignored or not allowed just in that...
Do common-source JFET amplifiers have an advantage over common-drain? The JFET would be in a low noise photodiode amplifier. The signal is 100us pulses with 10us raise times. Here are the schema...
I’d like to discuss how to report errors from C functions up the call chain. Consider firmware which communicates to handful of external peripherals (say over I2C and SPI), then validates the data...
I’ve got a simple circuit board where a PCA9554 is controlling the a switch MIC94090YC6. There’s a 100kΩ pull-down resistor. A GPIO pin on PCA9554 is an input on power-up. The leakage current fr...
I was looking for electret condenser microphone preamp topologies. I’d like the preamp to run on a single supply, so I’ll have to introduce an output offset. Saw two topologies for introducing th...
I’ve a linear sensor array (broadside). The array is 10m long and it contains 20 sensors. There’s a limit on the number of wires. I can have a handful of wires running the length of the array, b...
I’m trying to understand the biasing of a 2-terminal electret condenser microphone. The inner workings of a 2-terminal electret microphone are always drawn without a resistor at the JFET source. ...
I’d like to create a stable IR LED light source. I’ve read that LED efficiency changes with temperature. I’ve seen two designs which used feedback through light to correct the LED temperature dri...
I’m looking for circuits which convert differential current signal into single ended voltage. If found two topologies in application notes, and though of one more [obvious] topology myself. How d...
There are GFCI (RCD) units for DC. How do they sense the small DC current difference? I understand how GFCI for AC works. It uses a differential current sensing transformer with two opposing pri...
