I was looking for a simple per-amplifier circuit. Found one at http://www.minidisc.org/mic_preamp/Simple%20Stereo%20Electret%20Mic%20Preamp.htm. I made minor modifications and here is my version.
Lighting LED with AC main supply were not that easy. Mainly it required some sort of SMPS with current controlling circuitry. But it is changing. Now there are integrated circuits available specially designed to help to light LEDs with few extra components. One of such IC is CYT1000B. I like CYT1000B more compared similar ICs […]
Recently I created a soldering station based on Arduino Pro mini. It involves reading temperature data from thermocouple within soldering iron. Thermocouple produce a very little voltage, around up to 30 Milli volts for soldering irons. So, soldering station uses an op-amp based circuit to amplify those small signals from thermocouple to signal high enough […]
Here is the schematic and details for creating one channel relay module. It would be capable of driving both DC and AC current when appropriate relay is used. We can connect output pin of most of microcontrollers including Arduino to control it.