Oscillators
R2026bUse these examples to learn how to implement oscillators to produce periodic, oscillating electronic signals.
Featured Examples
Astable Oscillator
An implementation of an astable oscillator circuit. The circuit output voltage V2 oscillates in an unstable fashion between high and low states.
LC Oscillator Based on Colpitts Circuit
An implementation of a Colpitts oscillator circuit with a nominal frequency of 9MHz. The frequency of oscillation is given by 1/(2*pi*sqrt(L1*C1*C2/(C1+C2))). LC oscillators have good frequency selectivity due to higher Q levels than are achievable with RC oscillators.
PWM Circuit Using 555 Timer
A pulse-width-modulated (PWM) output implemented using a 555 Timer in astable mode. The duty cycle is set by a potentiometer, P1. The potentiometer is controlled during run-time via Duty Cycle Control Knob. The scope shows the resultant output from the 555 Timer. To end the simulation, click on the Stop button.
Model Triangle Wave Generator Using Operational Amplifiers
Model a triangle wave generator circuit by using two Band-Limited Op-Amp blocks. The first stage of the circuit represents a comparator constructed from an op-amp. Two Diode blocks model the Zener diodes that limit the output of the comparator to plus or minus 5 V. These limits result in a square wave.
Voltage-Controlled Oscillator with PI Control
A voltage-controlled oscillator with feedback control to regulate the output voltage. The oscillation frequency is controlled by the reverse bias voltage applied to the to the varactor diode. The model shows how behavioral and component-level modeling can be mixed when designing a circuit. Provided that the variable trans-conductance device has a fast dynamic response relative to the oscillation frequency, the implementation details are not important. Similarly, the PI controller is in abstracted form, and could either be implemented with op-amps, or in software.
