Free Circuit Diagram

Sine wave oscillator can be implemented using Wien-Bridge oscillator like in our previous sine wave oscillator circuit, but now we present another method of generating sine wave signal. Using phase shifter, we can build a simple sine wave generator, as shown in the schematic diagram below: Sine wave oscillator using phase shifter has [...]

This circuit is a simple crystal oscillator that can be operated in overtone mode. Overtone mode permit the operation at higher frequency than specified by the crystal. The circuit uses a grounded base amplifier configuration, and place the crystal as a series resonator. The transistor Q1 is biased in the active region as [...]

Quadrature oscillator generate two sine-wave signal, but one signal is shifted 90 degree from the other signal. One output that lead the other called cosine signal, and the other is called sine. Here is the schematic diagram of the circuit: This circuit is another type of pahase shift oscillator, with three phase shifter [...]

Bubba oscillator is another example of phase shift oscillator. The Bubba oscillator takes the advantage of quad op-amp package to get 45 degree phase shift for each section. The result is excellent d(phase)/d(t) to get very low frequency drift. Here is the schematic diagram of the circuit: Each RC section give 45 degree [...]

Sawtooth wave oscillator  circuit can be implemented using several methods, here we present one design that employs 555 IC.  Here is the schematic diagram of the circuit: The core of the circuit uses  general 555 oscillator configuration, but instead of using a fixed resistor to limit the current for charging the capacitor, we [...]

In designing small signal amplifier circuits, to achieve a specified amplifier gain we usually use opamp amplifier design to ease the setting of the gain. When the gain accuracy is not critical, we can use transistor feedback amplifier as the base of our amplifier design. Here is the schematic diagram of the transistor amplifier: [...]