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20MHz VCSEL 3mW Laser Test Circuit - This circuit takes advantage of some new
vertical cavity surface emitting lasers (VCSEL) that don’t require light output
control circuits. The circuit shows how to drive the device from a single high
speed CMOS IC. The circuit can easily be modified to transmit signals from
kilohertz to about 50MHz. ….(designed by David A. Johnson) |
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220 Volt Wiring Detector - This circuit senses power lines behind walls
(added 9/04) |
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220/230VAC Input 12VAC Output 100VA Max Halogen Converter - Fully Assembled
and Tested demo board CD including datasheets, application notes and ballast
design software Features: Short Circuit and Overload Protection, Fully dimmable
with all dimmer types, Compensated Load Regulation, Over temperature shutdown, EMI
Filter (added 3/05) |
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220V mains monitor - With this circuit you will be able to monitor the quality
of the mains. There are 4 distinct sections, each supervising a parameter
pertinent to the quality of the supply line. The noise section consists of a 50Hz
filter and a speaker where you will hear the noise present on the line. The
bicolor LED should be adjusted for the least light with the 5k pot and gives a
visual indication ... (added 9/07) |
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24-Bit ADC Measures from DC to Daylight - DN219 Design Notes (Linear
Technology) (app note added 6/06) |
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25 k Volt Generator Tests Insulation - 06/04/98 EDN-Design Ideas:
(design idea added 11/05) |
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250mW HF CW Transmitter - (circuit / schematic design added 6/06) |
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3 Digits Digital Volt Meter with PIC16F676 - This is simple 3-digits digital
volt meter.PIC16F676 used to read analog signal(voltage) and display the value on
3-digits 7-segment. You can apply similar principles to measure DC current with
parallel R shunt. ….(circuit design added 11/08) |
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3 GHz Divide by 1000 Prescaler - Converts 0.1, 3 GHz freqency to 0, 3 MHz,
extends frequency range measurements ….(design added 11/08) |
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3 Level Audio Power Indicator - Battery-operated3 LED display that connect it
to loudspeaker output (added 04/02) |
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3.3V converter delivers 3W from Li ION battery - 11/05/98 EDN-Design Ideas:
Lithium-ion batteries are rapidly gaining popularity in portable applications
because of ir superior energy density, low self-discharge rate, and high cell
voltage. When you use one Li-ion battery to power a 3.3V dc/dc
converter.....(design idea added 6/06) |
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3.3V Lithium Cell Supply Requires One Inductor - 08/05/99 EDN-Design Ideas:
Because of growing popularity of lithium-ion (Li-ion)batteries and 3.3V
power supplies, portable-equipment designers must often create a 3.3V supply that
a single Li-ion cell can power. fact.....(design idea added 09/05) |
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30 Meter QRP Transmitter for Morse Code - (Tony van Roon's circuit / schematic
design added 6/06) |
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300ma DC-to-AC Converter - This circuit was used to provide battery backup to
a device that had an AC (output) wall transformer. Due to quasi-sine-wave
output and imprecise 60Hz output frequency, some devices might not work properly.
Peak output is DC input voltage minus about 20 ohms drop. Use bigger output
MOSFETS for more current output. Designed by Andrew R. Morris (added
6/06) |
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3-30 V/2.5 A Stabilized Power Supply - The power supply is using a well known
and quite popular VOLTAGE STABILIZER IC the LM 723. The IC can be adjusted for out
put voltages that vary continuously between 2 and 37 VDC and has a current rating
of 150 mA …..(electronic design added 6/07) |
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3-Digit DVM Voltmeter - Uses 3161, CA3162 ICs ….(design added 11/08) |
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3-digit Volt / Amper Meter - Even if the digital multimeters have dominated in
a lot of applications, in the measurement, exist the need for existence of
instruments of clue in various appliances, voltage and current, as in power supply
or elsewhere. The circuits that give make this precisely the work, measure the
voltage in terminal a circuit and the current that passes in his. The circuit does
not present particular difficulties for somebody that has a small experience. The
two circuits are the himself, with a small difference only in their input, when
they have they measure voltage or current and in connection that concern decimal
point. ….(circuit design added 11/08) |
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3-Phase Power Meter Based on the ADE7752 - AN-641 Analog Devices Application
Notes (app note added 6/06) |
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4 to 20 Mloop Needs No External Power Source - 09/13/01 EDN-Design
Ideas: simple circuit in Figure 1 uses a low-current-drain
MAX407).....(design idea added 11/05) |
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40 Meter Direct Conversion Receiver - (circuit / schematic design added 10/06) |
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4000 series CMOS Logic Ics - There are many ICs in the 4000 series and this
page only covers a selection, concentrating on the most useful gates, counters,
decoders and display drivers. For each IC there is a diagram showing the pin
arrangement and brief notes explain the function of the pins where necessary. The
notes also explain if the IC's properties ....(circuit added 06/07/08) |
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40kHz IR Tester - Use this circuit to test if the light coming from your 40khz
IR emitter is really emitting the right frequency. The schematic says to use a
GP1U5X ir module, but probably any 40khz detector module will work....(circuit /
schematic added 6/05) |
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40kHz LED Test Signal Generator - This 40KHz crystal controlled oscillator
circuit drives an infrared LED with powerful 40ma pulses. The circuit can be
used to test optical communications circuits, designed to receive 40KHz modulated
light signals. ….(designed by David A. Johnson) |
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40MHz 32 Channel Logic Analyser - This project was published in Electronics
Australia in Oct/Nov 96. It is a 32 Channel, 40Mhz, fully PC controlled TTL/CMOS
logic analyzer with internal/external triggering and trigger delay. Internal
triggering is fully maskable (High/Low/Don't Care) on all 32 channels. The whole
things fits on one single sided PCB with virtually no wiring! ….(circuit design
added 11/08) |
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40MHz Frequency Counter Module - This circuit is ideal for adding a low cost
frequency display to a function generator or other design. I doubt if it is
possible to get a cheaper design using off the shelf components!. In fact, I
challenge anyone to make a cheaper design using garden variety components!. The
upper frequency limit is dependent upon the upper limit of the 74HC390 chips which
is roughly 40MHz. ….(electronic schematic added 11/08) |
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4–20ma Current Loop Tester - This circuit injects an adjustable current
through a wire loop. Using a digital current meter, the current can be
adjusted from near zero to over 24 milliamps. (added 12/04) ….(designed by
David A. Johnson) |
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4Channel Oscilloscope Adapter - will introduce the adapter to see the
wavefrom of four kinds of the signals at the same time with the oscilloscope on
these pages. At the classy oscilloscope, it is equipped with the function to see
more than one signal at the same time. The one which I am having can see only the
one signal. Therefore, I made the adapter to see four kinds of the signals at the
same time....(circuit / schematic design added 07/08/09) |
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5 Watt 80 Meter QRP CW Transceiver - A great deal of interest has been
generated by my previous design articles, so I decided to go to work on a full
blown transceiver design. After several months of work, the ROSE-80 transceiver
was born. This transceiver is similar to other designs but contains some unique
differences. This design boasts the following features...)schematic added 8/03) |
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50 MHz Frequency Counter - This project is nice and small frequency counter
that reads frequency from 1 Hz to 50 MHz that I have modified from original
designed by Weeder Technologies . I have designed new PCB to fit with 16X1 LCD and
change source code for compatible with new small PCB Specifications, Auto-ranging
with floating decimal point., Up to 7 digits displayed on 1X16 LCD.,
Auto-adjusting gate speed (0.1 sec to 1 sec)., Microcontroller-based circuitry
provides for simplicity, ease of assembly, and highly stable readout., Sensitivity
approximately 100 mV RMS (100 Hz to 2 MHz), 800 mV RMS @ 50 MHz., Input overload
protected. ….(electronic schematic added 11/08) |
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50 MHz Frequency Counter Voltage Meter and SwR/PWR Indicator - This is a
successor of the PIC16C71 4-digit LED f-counter & V-meter. Some hard to find parts
used in the previous version, which are out of production for some time, has been
omitted. A rather early PIC16C71 has also been replaced by 28-pin device
PIC16F876....(electronic schematic / circuit added 03/03/03) |
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500W low cost 12V to 220V inverter - Using this circuit you can convert the
12V dc in to the 220V Ac. In this circuit 4047 is use to generate the square wave
of 50hz and amplify the current and then amplify the voltage by using the step
transformer…..(circuit design added 09/08) |
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555 Go/No Go Tester - (Tony van Roon's electronic schematic / circuit added
4/02) |
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555 Timer IC Tester - (Tony van Roon's electronic schematic / circuit added
4/02) |
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5V/1A Power Supply - ….(circuit design added 08/08) |
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6 Digit 40MHz Frequency Counter Module - Here is design for a very low
cost 6-digit frequency counter module using of shelf components (and not
that expensive 74C926!). The standard circuit will display directly in Hz (1MHz
max), and re is a separate on board divider that will allow you to display
directly in KHz (approx 40MHz max). Because display reads directly in Hz or
KHz re is no .... (add 11/05) |
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741 Based Light Sensor - CdS photocell used for light/dark controlled relay
(Tony van Roon's electronic design added 4/02) |
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8 Hints for Better RF Signal Generator Measurements - Aligent Application Note
(app note added 04/05/06) |
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8 Hints for Making Better Spectrum Analyzer Measurements - Aligent App Note
(app note added 6/07) |
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8 Stage LED VU Meter - The circuit below uses two quad voltage comparators
(LM339) to illuminate a series of 8 LEDs indicating volume level. Each of the 8
comparators is biased at increasing voltages set by the voltage divider so that
the lower right LED comes on first when the input is about 400 millivolts or about
22 milliwatts peak in an 8 ohm system. The divider voltages are set so that each
LED....(circuit / schematic design added 6/06) |
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80 Meter CW ARDF Receiver - (circuit / schematic design added 6/06) |
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80 Meter DSB Transmitter - (circuit / schematic design added 6/06) |
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8038 Function Generator - Built around a single 8038 waveform generator IC,
this circuit produces sine, square or triangle waves from 20Hz to 200kHz in four
switched ranges. There are both high and low level outputs which may be adjusted
with the level control. This project makes a useful addition to any hobbyists
workbench as well. ….(electronic schematic added 11/08) |
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8038 Function Generator - Produces sine, square and triangle waves from 20Hz
to 200kH (circuit added 8/06) |
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8038 Generator - ICL8038 signal generator chip, manufactured by Intersil. An
improved version, made by Exar corp. is available (XR8038A). It can be used to
produce three types of waveforms, sine, square and triangle. The frequency,
amplitude and duty cycle can be varied, and selection of waveform is done
digitally. To further reduce the complexity, a 3-to-1 switch may be used in place
of the digital selection circuitry. I made use of the digital selection mechanism
because switches available on the market are prone to dirt accumulation and poor
contact quality. Besides, the digital method is a lot cooler! ….(electronic
schematic added 11/08) |
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9435 PCI Performance Measurements - Concepts and Practical Application -
Agilent Application Note (app note added 6/06) |
