In this post I have explained a variety of op amp preamplifier circuits, and there should be an appropriate layout here for almost any standard audio preamplifier application. As the name suggests itself, a preamplifier is an audio circuit which is used before a power amplifier, or between a small signal source and a power […]
Newly Updated Circuit Projects:
Laboratory Power Supply Circuit
Although a variety of laboratory power supplies have appeared in recent times, only handful of these will provide you with the efficiency, versatility, and low cost of the design detailed in this article. In this article I have explained a highly regulated, DIY, laboratory grade power supply with dual 0-50 volt. The voltage and current […]
Simple Touch Operated Potentiometer Circuit
In this touch operated potentiometer circuit we have two touch pads, which produce a slowly increasing voltage at the output when one touch pad is touched, and a decreasing voltage when the other touch pad is touched. When the touch contact is removed the voltage holds at that particular increased or decreased level “permanently”. Touch […]
Digital Theremin Circuit – Make Music with your Hands
Named after its creator, the theremin originated in the Soviet Union in the beginning of 1920’s. This comprised of a container installed with a couple of antennas. It did not have any keyboard to play, no strings like in guitars. Rather, the theremin made use of human body capacitance to manipulate the volume and the […]
Listen to UHF and SHF (GHz) Bands with this Simple Circuit
This simple two IC circuit can be used for capturing and listening to frequencies in the GHz range. Receivers designed to cover frequencies as high as several gigahertz (which is many thousand MHz!) are generally difficult to find, specifically for anyone who is looking for cheap versions of these gadgets. However, it may be possible […]
Bluetooth Stethoscope Circuit
In situations as critical as a COVID-19 pandemic, a doctor is the one personnel who is the most susceptible to getting infected by the virus from a patient. Therefore, doctors are being continually offered and equipped with many advanced and high tech devices in an effort to guarantee maximum safety to their life and health. […]




