Oscillator Circuits


Simple Oscillator / Pipe Locator

Sometimes the need arises to construct a really simple oscillator. This could hardly be simpler than the circuit shown here, which uses just three components, and offers five separate octaves, beginning around Middle C (Stage 14). Octave # 5 is missing, due to the famous (or infamous) missing Stage 11 of the 4060B IC. We […]


Very Low Power 32kHz Oscillator

The 32-kHz low-power clock oscillator offers numerous advantages over conventional oscillator circuits based on a CMOS inverter. Such inverter circuits present problems, for example, supply currents fluctuate widely over a 3V to 6V supply range, while current consumption below 250 µA is difficult to attain. Also, operation can be unreliable with wide variations in the […]


Safe Oscillator For Watch Crystals

This circuit was developed to allow watch crystals to be used in an existing CMOS oscillator circuit that was to run from a 12V supply. The problem is that these crystals only work up to a supply voltage of about 6V. Any more than that and the crystal will be over-driven, causing it to shatter. […]


General Purpose Oscillator

The oscillator shown in Figure1 is frequently used in digital circuits and may, therefore, look very familiar. Many readers may not know that this type of oscillator suffers from a nasty draw-back caused by noise. When the amplitude of the noise is higher than the hysteresis of the gates used for the oscillator, spurious switching […]


LED Torch Uses Blocking Oscillator

This simple LED torch is driven by a 2-transistor blocking oscillator which steps up the voltage from a 1.5V cell. It relies on the inherent current limiting of the 150µH choke to protect the white LED from over-drive. With a 9V zener diode in place of the white LED, it could also provide a 9V […]


10 to 1000 MHz Oscillator

Nowadays, it is no longer necessary to use discrete components to build oscillators. Instead, many manufacturers provide ready-made voltage-controlled oscillator (VCO) ICs that need only a few frequency-determining external components. One example is the RF Micro Devices RF2506. This IC operates with a supply voltage between 2.7 and 3.6 V (3.3V nominal) and provides a […]


Comparator Based Crystal Oscillator

Although a simple crystal oscillator may be built from one comparator of an LT1720/LT1721, this will suffer from a number of inherent shortcomings and design problems. Although the LT1720/LT1721 will give the correct logic output when one input is outside the common mode range, additional delays may occur when it is so operated, opening the […]


MSF Radio Time Clock

    Introduction The National Physics Laboratory broadcasts a time signal, previously known as the Rugby clock but now called "Time from NPL." Its most commonly known as the MSF signal due to it originally being identified in Morse code those letters. It is broadcast from Anthorn on 60kHz. Many commercial clocks use it to […]


50Hz 60Hz Frequency Generator Circuit Using Crystal Oscillator

50 Hz 60 Hz frequency generator circuit using crystal oscillator You can generate 50Hz or 60Hz using this frequency generator. This oscillator can be used as the front end of circuits that require precision pulses. A crystal is used in the circuit to generate clock pulses. The circuit uses two counter ICs CD4060 and 7490 […]


Charge Pump Voltage Controlled Oscillator Circuit

The charge pump has many applications. While we generally think of power supply applications, it is also very useful in this voltage controlled oscillator. This VCO has a number of useful features including single positive power supply operation, positive VCO reference voltage, fast response, high linearity, temperature compensation and open collector output. Seldom are all […]