Free Circuit Diagram

In some PLL application, sometimes we need to provide lock indication when the PLL is in locked state. The simplest one is binary indication, 0 or 1 to correspond with lock/unlock condition. This  condition should be easy to be presented with a LED lamp. The schematic diagram  shows a lock-detection scheme [...]

This dynamic compressor will give about 20dB compression, at very wide input signal range 100 mV to 10 V.  Another advantage of this circuit is that this circuit doesn’t need any power supply, we call it self powered, or more accurately, signal-powered compressor. Here is the schematic diagram of the circuit: A part [...]

Notch filter is known as band-cut filter or band-reject filter. The fuction of this filter is to remove some frequency portion of a signal. The schematic diagram of this filter circuit, a second order notch filter is depicted in the figure below. The formula is actually complicated, but by taking the R3=R4 and [...]

ROHM (www.rohm.com) is originally a resistor producer company, but finally expand their business and produce monolithic IC, and this one used in our circuit is the example. The internal structure of this FM transmitter integrated circuit consist of stereo modulator that creates a stereo composite signal, an FM modulator that modulate a carrier frequency with [...]

Designing passive crossover network for your speaker system is easy, just like what shown in our previous crossover design article, but now we can design many types of crossover even easier using online crossover design tool. The crossover schematic diagram here is an example  with a case of 10 kHz high corner frequency, 1250 Hz  [...]

A LT1637 is advertised as 1.1MHz, 0.4V/us Over-The-Top Micropower, Rail-To-Rail Input and Output Op Amp. This features are suitable for current sensing application since input voltages are right at the upper rail. The circuit show current sensing of 5V supply system, but  monitoring up to 44V application can be done by this circuit  (the maximum [...]