Converters - Voltage to Frequency and Voltage Controlled Oscillators (VCO), page 3


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Converters: Voltage to Frequency, Page 3
Voltage Controlled Oscillators (VCO)
VCO; Voltage to Frequency Converters: #'s - A B - K L - U V - Z
Last Updated on: Friday, September 19, 2008 04:14 AM

Circuits Designed by Dave Johnson, P.E. :

200MHz - 400MHz VOLTAGE controlled OSCILLATOR
If you need a clean emitter coupled logic (ECL) type signal between 200MHz and 400MHz this circuit works fine. It uses four voltage controlled capacitors to change the frequency.

40KHz Voltage to Frequency Converter
This circuit was designed to frequency modulate a 40KHz carrier, using human voice frequencies. A common flip/flop is used at the core of the circuit. (added 12/04)

AIR TRANSPARENCY MONITOR, XENON FLASH RECEIVER
This is Page 2 of the receiver circuit

CMOS SCHMITT TRIGGER IC MAKES VCO
By changing the supply voltage fed to a classic 4584 Schmitt trigger type oscillator, the oscillator frequency can be changed over a range of 50:1. A 74HCU04 inverter is used at the output of the 4584 to maintain a constant TTL logic level signal.

Light to Frequency Converter
This circuit uses a CMOS version of the classic 555 timer, to form a light intensity to frequency converter. A small PIN photo diode is used as the light detector. The pulses produced are short, so in some applications you may want to stretch them or feed them through a flip/flop to produce a square wave signal. Although the circuit shown is designed for a 5v supply, it could operate from almost any voltage from 3v to 15v.

VOLTAGE TO FREQUENCY CONVERTER + 1uS LED PULSE DRIVER
This circuit receives the signal from the above amplifier and launches powerful 1uS infrared light pulses from a low cost LED that are frequency modulated by the audio information. The 10KHz center frequency of the pulse stream is low enough so a standard infrared LED can emit ten times more light than conventional long pulse techniques. The circuit is described in more detail in the transmitter section of my Handbook of Optical Through the Air Communications.

Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:

Keys to Longer Life for CMOS: AN-349 Analog Devices Application Notes (app note added 2/06) Here's How CMOS Can be Protected Against Abuse

Mixed Signal Circuit Technologies: AN-280 Analog Devices Application Notes (app note added 2/06) Considers problems which arise when reality (& Murphy) intervene in a design which otherwise seems satisfactory in terms of theory and modeling.

Multilayer Capacitor Doubles as Varactor: 03/20/03 EDN Design Ideas / (added 1/05) The main purpose for building the circuit in Figure 1 is to study the idiosyncrasies of X5R, Z5U, and Y5V multilayer ceramic capacitors. The circuit is also an inexpensive VCO (voltage-controlled oscillator) with only five components. Many types of ceramic capacitors for surface-mount placement are on the market....

Operation and Applications of the AD654 IC V-to-F Converter: AN-278 Analog Devices Application Notes (app note added 2/06)

PIC controlled DDS VFO 0 to 6 MHz: (circuit added 7/02)

Programmable Clock Oscillator: voltage controller oscillator that was designed as a wide range oscillator to generate clock pulses for a stepper motor drive system, frequency could be varied over1,000,000:1 (added 5/02)

VCO; Voltage to Frequency Converters: #'s - A B - K L - U V - Z