Free Circuit Diagram

Op-amps has been widely used in low frequency oscillator (frequency <= 100kHz), but we can actually use it for high frequency crystal oscillator as long as we have an op-amp with the proper bandwidth. An excellent gain stages can be implemented using LT1190 and LT1191 op-amps. Here is the schematic diagram of the circuit: [...]

A square wave oscillator using 555 IC can be configured to give symmetric oscillation (50% duty cycle). Other circuit uses diodes to split the charging and the discharging paths through different resistors, but here we need no such diodes. Here is the schematic diagram: The time period for the output high is the [...]

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 [...]

The frequency formula of 555 oscillator is popularly known. For a known resistors and capacitor, the frequency can be determined by a formula. From the math logic, if the frequency and the resistors are known, then an unknown capacitor could be determined by the inverse of the formula. Anyone who has a frequency counter are [...]

This audio frequency meter uses 555 IC as a monostable multivibrator (one-shoot trigger). A monostable multivibrator can act as a frequency-to-voltage converter because it produce a fixed pulse width, with the repetition rate/density is proportional to the triggering input frequency. Here is the circuit’s schematic diagram: For resistor R1, because it set the [...]

Waveform generator is very useful in electronic experiment and design. This circuit generate sine wave oscillation, but actually we can modify the circuit to generate triangle or square wave function. Lets see its schematic diagram first, here it is: The core of this waveform generator is MAX038. This integrated circuit chip gives complete [...]