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Voltage Comparator Circuits Last Updated on:
Monday, October 03, 2011 06:09 PM
Circuits Designed by Dave
Johnson, P.E.:
12V Cooling Fan Thermostat This circuit will
turn on a 12v DC powered cooling fan when the air temperature reaches a certain high
temperature and will keep the fan turned on until the temperature drops below a
second lower level. Both the high and low temperatures are both adjustable.
For ease of use, the temperatures are proportional to either degree F or degrees C,
using an accurate electronic sensor.......
40KHz Ultrasound Receiver
A X100 transistor amplifier is followed by a zero cross detector circuit, using a
voltage comparator. The output is a TTL logic signal, corresponding to the
received 40KHz signal. (added 7/06)
PRECISION ULTRA LOWER POWER OSCILLATOR
This circuit works much like the classic 555 timer, but draws only about 1.5
microamps from a 3 volt battery. It is highly stable under varying temperature and
supply voltages.
Wide Band Zero Cross Detector
This circuit was designed to convert a low amplitude 40KHz signal into a clean
square wave signal. It will work with inputs as small as 5mv peak-to-peak or
as large as 3 volts peak to peak. The input frequency can range from a few
kilohertz to about 150KHz.
Links to electronic circuits,
electronic schematics, designs for engineers, hobbyists, students & inventors:
12V Cooling Fan
Thermostat This circuit
will turn on a 12v DC powered cooling fan when the air temperature reaches a
certain high temperature and will keep the fan turned on until the
temperature drops below a second lower level. Both the high and low
temperatures are both adjustable. For ease of use, the temperatures
are proportional to either degree F or degrees C, using an accurate
electronic sensor.......[circuit
designed by Dave Johnson]
40kHz Ultrasound Receiver - A X100 transistor amplifier is
followed by a zero cross detector circuit, using a voltage comparator.
The output is a TTL logic signal, corresponding to the received 40KHz
signal.... [Designed by David A. Johnson]
Precision Ultra Lower Power Oscillator - This circuit works much like the
classic 555 timer, but draws only about 1.5 microamps from a 3 volt battery. It is
highly stable under varying temperature and supply voltages.... [Designed by David A.
Johnson]
Voltage Comparator Switch - This circuit will provide an indication whenever
the input voltage differs from two defined limits, V1 and V2. The supply voltage, Vcc
must be higher than the highest input voltage by at least 2 volts. One application
here is to monitor a 12V car battery....(electronic schematic / circuit added 4/02)
Wide Band Zero Cross Detector - This circuit was designed to convert a low
amplitude 40KHz signal into a clean square wave signal. It will work with inputs
as small as 5mv peak-to-peak or as large as 3 volts peak to peak. The input
frequency can range from a few kilohertz to about 150KHz. …. [Designed by David A.
Johnson]
