Free Circuit Diagram

The AD623 is a single chip instrumentation amplifier. The internal circuit is based on a modified classic three op amp approach to assure single or dual supply operation even at common-mode voltages at the negative supply rail. Some key features are: Low voltage offsets, input and output, as well as absolute gain accuracy, and one [...]

This FM transmitter circuit is small, similar to our previous single chip FM  transmitter, but this FM transmitter is monophonic. You can see in the circuit’s schematic, the left and right signals is mixed before modulate the radio frequency. Here is the schematic diagram of the circuit:   The core of this [...]

Using VFC110 chip, we can build a high frequency voltage-to-frequency converter. The features of this chip include the capability of high frequency operation, disable function, and an on-board precision 5V reference. This precision reference can be used to provide reference for offsetting the VFC transfer function, as well as provide transducer or bridge excitation. As [...]

The LM1894 is a stereo noise reduction circuit suitable for audio playback application. The DNR system is non-complementary, meaning that it does not require encoded source signal. The system is compatible with almost all prerecorded tapes and FM broadcasts. This noise reduction system uses  psycho-acoustic masking and an adaptive bandwidth filtering to achieve 10 dB [...]

This simple Batteries charger circuit is designed for NiMH/NiCd batteries. It need no micro-controller nor any programming. Linear Technology Corporation produce the LTC4060, an autonomous 1- to 4-cell, 0.4A to 2A linear NiMH and NiCd battery charger complete controller. Here are the main features: No Sense Resistor or Blocking Diode [...]

Thermocouples give many benefits compared to thermistor/RTD (Resistance Temperature Devices).  Some advantages of thermocouple are their wider temperature range, their reliability, and their consistency over long period of time. In some cases,  thermocouple calibration  is even unnecessary. Thermocouple temperature sensors are widely used in temperature controllers for boilers, oven,  pressurized reactor, even in high temperature [...]