Free Circuit Diagram

Ionization-based smoke detectors are efficient and cheap, so they are often installed in the house, other outbuildings, and  the garage. The Locations of the device is far from house, so we need to transmit the alarm signals back into central home-security system or the house. This is a simple circuit that sense a supply current [...]

To know someone is lying  or not we can use lie detector. This is a simple lie detector that can be made in minutes. It works to detect the someone who telling lie but it is not as sophisticated as the ones the professionals use. Here is the schematic diagram of this circuit: [...]

Fast peak detector requires special amplifier features. The output stage must have high slew rate to keep up with the intermediate stages of the amplifier. This condition causes either a long overload or DC accuracy errors. The amplifier must deliver large currents into the capacitive load of the detector to maintain a high slew rate [...]

The circuit below is a schematic diagram of a fast pulse detector. At 100 ns  or wider pulse width, the detection should be error free. At 60 ns pulse width,  the detection error should be under 10%. This circuit should be used to detect at least 100 ns wide pulse to ensure an [...]

This circuit is similar to peak detector, but the the output won’t immediatelly follow the input peaking. Because the output follow the input peak slowly,  averaging effect will be seen at the output. In the figure below you can see the circuit’s schematic diagram. Use 1% resistor for R1, R2, R3, and R4, [...]

A simple half-wave peak detector using a single transistor is very compact and low cost, but if the application require precise detection for signal under 100mV then that circuit become useless. Here you can use more precise half-wave peak detector circuit using only a single op-amp with few passive components. Look at the circuit’s schematic [...]