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Light Level Indicator (Window Comparator) - The second example below uses a LDR (light dependent resistor) to indicate some desired light level. The LDR has a large dynimic range and varies in resistance from less than 100 ohms on a cloudy day to over a megohm in total darkness. A 2K pot was used to adjust the window range for usual room light conditions. This setup might also be used to indicate sunrise/sunset conditions. __ Designed by Bill Bowden Light Pulse Receiver (2uS) - Although the LF357 is an obsolete part, this circuit gives you an idea how to build a sensitive modulated light detector with high ambient light immunity. The first section uses a 100mH inductor as an efficient photodiode current to voltage conversion circuit . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2002
Light Receiver 30Khz Amp - This circuit uses NPN darlington transistor to amplify the signal produced from short light flashes, as detected by a PIN photo diode. The circuit draws only about 330uA from a 6v battery . . . Hobby Circuit designed by David Johnson P.E.-March, 2002
Light Receiver Amp-40Khz - This circuit is similar to 30KHZ LIGHT RECEIVER AMP but provides more gain and operates up to 40KHz. However it draws more power supply current. . . . Hobby Circuit designed by David A. Johnson P.E.-March, 2002
Light Receiver Works from 1Khz to Over 70Mhz - This circuit uses one tiny C-MOS inverter IC to form a modulated light receiver with a very fast response. it is designed around a PIN photo diode that is packaged for use with plastic optical fibers. it can be used as an optical fiber receiver. By using the open end of the optical fiber it can "sniff" out any modulated light signals. . . Circuit by David Johnson P.E.-June, 2000
Light Receiver-10MHz to 20MHz - Light power to volts conversion = APPROX.15mV per microwatt at 850nM . . . Hobby Circuit designed by David A. Johnson P.E.-July, 2006
Lightening Detector - A VLF receiver tuned to 300 kHz designed to detect the crackle of approaching lightning. A bright lamp flashes in synchrony with the lightning bolts indicating the proximity and intensity of the storm. it has a superior RF section with a single resonance near 300kHz and plenty of sensitivity. The antenna is a telescopic antenna that extends to two or three feet __ Contact: Charles Wenzel of Wenzel Associates, Inc.
Lightning Simulator - This little simulator generates short pulses at a few Hz rate and is heLPFul in designing and testing lightning detector circuits like the one at the top of the page. The output is connected to a shielded audio cable with an RCA type connector. The other end of the cable is connected to the antenna of the lightning detector through a 10 pF capacitor (not shown). The shield of the audio cable is connected to the detector's ground. The 10 pF allows the lightning detector's tuned circuit to ring and the amplitude of the ring may be observed on the collector of Q1. The circuit is built into a Home Depot gift certificate can. The circuit board slides into two card guides glued to the ends of the can. Any type of construction will probably work fine, but a metal can is recommended to keep the pulses "contained. " __ Contact: Charles Wenzel of Wenzel Associates, Inc.
Limiting Amplifier Forms AM Modulator - 12/07/95 EDN Design Ideas: he wideast use of limiting amplifiers is for clamping analog signals within a desired range. However, limiting amplifiers with fast overdrive-recovery times and wide bandwidth have an interesting additional application: You can use these amplifiers to form AM modulators. Typically, you provide dc voltages for the high and low clamp levels, and the amplifier limits its output range to those levels, regardless of the input overdrive. Properly designed limiting amplifiers have a fast overdrive-recovery time, which allows them to quickly return to linear operation when the input falls within the clamp levels. Design by Ronald Mancini and Mark Amarandos, Harris Semiconductor Melbourne, FL, and Costa Mesa, CA-- 12/07/95
Linear FM 50Watt with BLY90 - A amplifier of force RF for the FM, is always essential for the amateur that wants it strengthens some small transmitter, that likely already it has manufactured or has been supplied ready. The present circuit can give 50-60W RF force of expense, with control smaller than 15-20W in the region of frequencies of FM, that is to say in the 88-108MHZ. Transistor that we selected for __ Contact IQ Technologies
Liquid Level Receiver - Schematic __ Designed by Jon Fick
Long Loopstick AM Radio Antenna - Wound on a 3 foot length of PVC pipe, the long loopstick antenna was an experiment to try to improve AM radio reception without using a long wire or ground. it works fairly well and greatly improved reception of a weak station 130 miles away. A longer rod antenna will probably work better if space allows __ Designed by Bill Bowden
Low Cost 4Mbps IRD Receiver in MS8 & SO-8 Package LT1328 - DN152 Design Notes__ Linear Technology/Analog Devices
Low Cost Mixer - A simple mixer circuit suitable for mixing microphones or effects outputs. The overall gain from input to output is one if the pot related towards the input is full up. You'll be able to generate this a net gain of ten (or any other reasonable gain) by lowering the input resistor towards the second op amp.10K in this position provides a gain of 10db, or 20db.__
Low Cost‚ High Performance Receiver for Wireless Applications 1/16/94 - App Note Doc #904 1/16/94 __ California Eastern Laboratories
Low Distortion IF Amplifier/ ADC Driver with Digitally Controlled Gain - LT5524__ Linear Technology/Analog Devices
Low Frequency Block Converter-Converts VLF/LF bands to shortwave frequencies - This converter shifts the VLF/LF bands, from below 20 kHz to over 350 kHz to the shortwave frequencies, determined by the selected crystal. in this prototype, the crystal frequency is 5 MHz, so the LF band comes out at 5.02 MHZ to 5.35 MHz, suitable for use with a shortwave receiver. Notice the lack of an expensive mixer or special IC ! __ Contact: Charles Wenzel of Wenzel Associates, Inc.
Low Frequency Phasing Exciter - As of this writing, two programs are available for data transmission at low frequencies that use a computer sound card and output the audio in an i/Q format. JASONhas a unique FSK format with a variety of data rates. The "DigiMode Terminal" in Spectrum Laboratorygenerates PSK and MSK signals suitable for LF work. if you are new to all of this, check out the Low Frequency Transmission Mode article on this site __ Designed by John K. Andrews Holden, MA FN42ch w1tag @ charter.net
Low Noise AC Amplifier with Programmable Gain & Bandwidth - Two LTC6910 programmable gain amplifiers can be combined to provide independent gain and bandwidth control using two 3 bit digital words. The Gain Control PGA simply varies the circuit gain from 1 to 100. The Bandwidth Control PGA puts signal gain inside the feedback loop of the amplifier. As this gain is increased the effective value of feedback resistor R2 is decreased. This pushes out the upper low pass corner frequency of the ac amplifier. __ Linear Technology/Analog Devices App Note, Mar 16th 2010
Low Pass Filter for FM 88-108 MHz - Filter used for eliminate unwanted harmonic frequency at second and third. Notch filter, Band Pass Filter (BPF) , and High Pass Filter (HPF) sometime combined in constructing LPF design. Schematic below for FM Broadcast Lowpass Filter 88-108 MHz__
Low Power 100khz Light Receiver - By starving a high speed logic inverter for current, this circuit can produce a sensitive 100KHz light receiver circuit, which is immune to ambient light, but only drawing 100 micro amps from a 3 volt supply. . . Circuit by Dave Johnson P.E.-April, 2005
Low-Noise PIN diode laser receiver - This article will describe a simple low noise PIN diode front end suitable for laser communications. Two schematics are presented, one for nighttime use and one for daylight use. Although it may be possible to add switching to the front end to allow one front end to work for both night and day I decided against this due to the extremely high impedance involved and degradation associated with loading on the PIN diode. __ Designed by John - K3PGP
LowPass Filter - The schematic you find here comes from another site on the internet, but because it's on so many sites, we don't know who actually designed it. However it's a nice one. Capacitors: C1, C4 22pF cer. C2, C3 51pF cer. Coils: L1, L2, L3 #18 bus wire, 1/4"diameter, 3 turns * Form the leads from the capacitors as shown in the little figure below. Then solder them from the pad to the outside ground area. * Be sure that the turns from the coil are seperated by the same distance as the diameter of the wire * Form the leads from the coils as shown in the little figure below. Then solder them in place. * Place the filter in a metal box, with rf-connectors on both ends (SO239 (=PL259) , BNC or N-connectors) __
Low-Power IC Packs GPS Receivers 7/31/01 - App Note Doc #953__ California Eastern Laboratories
Low-power, super-regenerative receiver targets 433-MHz ISM band - 02/02/06 EDN Design Ideas: Good for power-miserly battery-powered, shortrange, wireless applications Design by Cedric Mélange, Johan Bauwelinck, and Jan Vandewege, Ghent University, Ghent, Belgium
LT1328: a Low Cost 4Mbps IrDA Receiver in MS8 & SO-8 Package - DN152 Design Notes__ Linear Technology/Analog Devices
LTC Design Note: High input IP3 mixer enables robust VHF receivers - 08/29/14 EDN Design Ideas: LTC Design Notes 515: An increasing number of applications occupy the 30MHz to 300MHz very high frequency (VHF) band. Television and radio broadcasting, navigation controls and amateur radios are a few examples. Modern RF component development is aimed at much higher frequency bands used for voice and data communications systems Design by Andy Mo
LW/MW/SW Shortwave general coverage receiver - Ham Radio - V-U) HF AMPLiFiER - Schematic __ Designed by Guy Roels ON6MU |
