Free Circuit Diagram

Current loop interface has been widely used in industrial environment because it’s robustness. Noise resistance and fail detection capability  made it suitable for long distant transmission in harsh environment. This circuit provide current loop transmitter for temperature sensor. Here is the circuit’s schematic diagram: The temperature measurement is done by LM35 temperature sensor [...]

The excellent high input impedance, high slew rate, and high voltage qualities of CA3140 op-amp make it suitable for Wien-bridge sine wave oscillator. The basic circuit for Wien-bridge sine wave oscillator is shown in the figure below (the upper part). You can see the formula in the figure, when R1=R2=R, and C1=C2=C, then the formula [...]

Using a single supply quad comparator LM339, LM239, LM2901, LM2901V, NCV2901, or MC3302, we can build a square-wave oscillator with simple circuit and formula. Here is the schematic diagram: This circuit is suitable if you need  many square-wave oscillators in one circuit, since the quad packaged comparator provide four comparators in one single  [...]

The simple low-pass filter is shown in Figure below. The filter has a 20dB/decade roll-off after its corner frequency fc. Its low-pass frequency gain (f->0) is defined by R3/R1. This allows low-frequency gains other than unity to be obtained.  R2 should be chosen equal to the parallel combination of R1 and R3 to minimize error [...]

This circuit is similar to our previous tone control circuit, a bass-treble tone control circuit, but here we present the formula for design your tone control’s custom frequency response. Here is the schematic diagram and formula of the tone control circuit: Almost all op-amp type can be used, as long as they have [...]

High voltage current sensing/monitoring can be designed using LTC6101 op-amp. The following current sensing circuit is capable of measuring electrical current in 500 volts system. Here is the schematic diagram of the circuit: Two external Mosfets is added to hold off the voltage, allows the LTC6101 to be connected to a very high [...]