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Electronics Schematics - M

Miscellaneous Circuits

$5 junk box Circuit Determines Phase Sequence : 04/23/98 EDN-Design Ideas

4  to 20 mloop needs no external power source: 09/13/2001 EDN - Design Ideas / The simple circuit in Figure 1 uses a low-current-drain MAX4073H amplifier to sense the current flowing through a 4- to 20-mA loop. The circuit senses the current through a 1O resistor with a fixed gain of 100 and uses no battery or dc power supply.

48 input×16 output cross point IC eliminates the need for multiplexer amps: 02/20/03  EDN-Design Ideas / Cross point switches are ideal for use in video-security systems, which accept multiple camera inputs while providing playback and multiple loop-through to multiple monitors.

Analog Encoding: Convert switches and sensors into DMX signals. Uses are found in Haunted houses, stage plays, themed events, holiday light animations, anytime you want to control DMX compatible equipment. Fog machines and strobe lights can be independently controlled be remote switches or sensors.

Audio Signal Source:

Auto referencing circuit nulls out sensor errors: 01/24/2002  EDN - Design Ideas / The auto referencing circuit in Figure 1 nulls out the error of a sensor, such as a pressure transducer, at its reference level-for example, at ambient pressure. The circuit is an analog-digital-feedback control system that uses a digitally programmable potentiometer to provide the variability. .

CEMF (counter electromotive Force) Charger

Circuit avoids metastability: 08/30/2001 EDN - Design Ideas / Consider a computer system that has a host processor connected to a remote-I/O subsystem (Figure 1). The host clock treats the I/O system, which is located far from the main hardware, as a slave. Because of the transmitters, receivers, remote-system logic, and cable length, the data the host receives has a dramatic latency.

Circuit Disconnects Load From Low voltage Supply: 04/24/03 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit

Circuit Forms gamma photon Detector: 04/24/03 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit

Circuit gang programs EEPROMs over I 2 C bus: 09/13/2001 EDN - Design Ideas / You use the fully controlled circuit in Figure 1 to parallel-program two-wire serial EEPROMs via the I2C bus. Gang programmers must address all memory devices during a write operation. To verify the memory contents, however, the system must address only one memory at a time during read operations. .

Circuit improves further on first event detector: 06/27/2002  EDN - Design Ideas / The circuits in Figure 1have certain advantages over those in a previous Design Idea (Reference 1). The first-event detector with auto reset (Figure 1a) consists of N sets of monostable multivibrators, using 4001 logic circuits with LEDs attached. After any player (1 through N) presses a pushbutton, the corresponding monostable multivibrator switches on, and its associated LED

Circuit produces variable frequency, duty cycle: 07/24/03  EDN-Design Ideas /  This Design Idea shows a simple, low-cost circuit that produces a highly accurate variable-frequency and variable-duty-cycle output (Figure 1). Further, the duty cycle and frequency are independent of each other (excluding 0 and 100% duty cycle).

Circuit provides leading edge blanking: 05/29/03  EDN-Design Ideas / In isolated switch-mode power supplies using peak-current-mode control, generally the current-sense resistor senses the current on the primary side of the power converter. Figure 1 shows a typical circuit, in which R2 is the current-sense resistor that monitors the current.

Circuit translates I 2 C voltages: 12/26/2002  EDN - Design Ideas /  This Design Idea explores level-shifting an I²C bus from 5V/ground (positive domain) to ground/25V (negative domain). In multi supply systems, you sometimes face a situation in which digital information stored in logic circuits running from 5V to ground needs conversion to analog signals referenced to a negative supply..

COCKCROFT and WALTON VOLTAGE MULTIPLIERS: Here are some applications of the Cockroft-Walton voltage doubler circuit for generating high voltages from a low voltage AC source. The circuit is quite practical for generating thousands of volts (or more) or just a few volts at high current.

Combinational Conjuring Trick:

Conjuring Trick:

Consider The "Deboo" Integrator for Unipolar Noninverting Designs : 03/18/02 Electronic Design - Ideas for Design / The design of a standard inverting integrator is simple when bipolar supplies are available, but it's cumbersome with a unipolar supply. To allow adequate headroom for the output, the circuit must be biased away from ground, often at half the supply.

Converter ignores Power Supply Variations: 01/05/95 EDN-Design Ideas

DEER REPELLENT:  Here is a simple sensor, which can detect the seismic vibrations caused by a person or large animal walking nearby. A representative application for the sensor is a deer repellent for the vegetable garden. When a deer steps near the sensor a loud buzzer or beeper sounds for a few seconds startling the would-be vegetable thief away.

Deer Repellent: seismic sensor

Diodes improve inverter Efficiency: 04/29/99 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit

Door/Window Sensor Resists Tampering: 01/21/99 EDN-Design Ideas /  PDF contains multiple circuits - scroll to find this circuit

Doorbell for the Deaf:

Ease Capacitor ESL/ESR Measurement With MercuryWetted Relay : 11/25/02 Electronic Design - Ideas for Design / Capacitor discharge circuits are used extensively in fast pulse generation.

Electric Discharge Tubes:

Electromagnetic Field Detector: This circuit is sensitive to low frequency electromagnetic radiation and will detect for example hidden wiring or the field that encompasses a transformer. Pickup is by a radial type inductor, used as a probe which responds well to low frequency changing magnetic and electric fields. Ordinary headphones are used to for detection. The field that surrounds a transformer is heard as a 50 or 60Hz buzz.

Electronic Coin tosser:

Electronic fish lure :

Electronic Fish Lure:

Electronic Jam:

Electronic 'snap': First Response Monitor

Fast Compact Routine Interfaces EEPROM to  µC : 03/04/99 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit.

Flash Memory Anticipates Architecture Transformation: 02/20/03 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit

Foreign Vocabulator Recollector: It was designed especially to learn German and Russian words, in a random multiple-choice format. 

Frequency Dependant Negative Resistor (Using OpAmps):

Frequency source feeds entire lab: 01/23/03  EDN-Design Ideas / Plumbing a laboratory with a standard frequency makes a lot of sense if the lab uses multiple frequency counters, spectrum analyzers, and other frequency-dependent test equipment.

FUN CIRCUITS: This pdf document consist of 5 individual circuits to have fun with some of the titles include smell a vision, the dripper and remote control blocker well worth a look.

Gag Circuits: magic lamp, dripper (improved!, remote control jammer

Get more power with a boosted triode: 04/03/03  EDN-Design Ideas / Even though 6L6 beam-power tubes have been around for 66 years, they are still quite popular for use in electric-guitar amplifiers, and its cousin, the 6CA7 (EL34) power pentode, is a favorite among audiophiles. The developers of these tubes designed them for pentode-mode operation, and they deliver maximum audio power in this mode.

Get more power with a boosted triode: 06/12/03  EDN-Design Ideas / This Design Idea is a reprint of an earlier one that contained errors in graphics (Reference 1). Even though 6L6 beam-power tubes have been around for 66 years, they are still quite popular for use in electric-guitar amplifiers, and its cousin, the 6CA7 (EL34) power pentode, is a favorite among audiophiles.

Hardware Accelerator Targets Cosimulation: 02/20/03 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit

HeNe & Solid State Laser Power Supplies & Notes (similar to Above):

Hierarchical Priority Encoder:

High side driver has fault protection: 09/05/2002  EDN - Design Ideas / High-side drivers find common use in driving grounded solenoid coils and other loads. Short-circuit protection for such drivers is essential for avoiding damage from wiring faults and other causes. Polymer fuses are generally too slow, and discrete current-limiting circuits are large and cumbersome.

Hot Swap Structure offers Improved Redundancy: 01/09/03 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit -- For redundancy purposes, a number of power supplies, using ORing diodes, can work into the same load. During maintenance, when you can remove any power supply, the minimum possible power perturbation at the load is desirable.

Hot Water Tank Indicator:

IC maintains uniform bias for GaAs MESFETs: 08/22/2002  EDN - Design Ideas / The gate-turn-on threshold voltage for GaAs MESFETs (gallium-arsenide metal-semiconductor field-effect transistors) varies considerably from part to part, even within a given lot. That behavior makes biasing difficult, especially if you want to design the device into a high-volume product.

Inductance Substitution Circuit Uses Variable Coils : 01/07/02 Electronic Design - Ideas for Design / When prototyping RF circuits, computer simulation or de-sign programs can potentially yield the wrong component values.

Inexpensive XRay Machine #1:

Invisible Broken Wire Detector:

Jacob's Ladder, How to Make One :

Jacob's Ladder:

Laser Communication System: This is a simple Laser communication system. It can transmit and receive signal from any audio device. Communication distance is few meters. All components are not critical. Transistor 2N2222 may be on the coolrib. Laser diode is from laser pointer

Laser Printer Prototypes PC Board Artwork: 05/12/94 EDN-Design Ideas  

LC Filter Design:

LED Torch:

Lightening Detector:

Magic Lamp: Old idea, newtwist.

Magic Wand:

Magnetic Gun: When optimally tuned, it will propel a small slug about 1.5 metres high, or 2.5 metres horizontally

Magnetic Levitation Circuit:

Mega phone circuit 9v:

Multilayer capacitor doubles as varactor: 03/20/03  EDN-Design Ideas / 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.

Negative Resistance Increases inductor's Q: 03/30/95 EDN-Design Ideas

NEGATIVE SUPPLY FROM SINGLE POSITIVE SUPPLY: Op amps are very useful. But one of their major drawbacks is the requirement of a dual supply. This circuit solves the problem to a certain extent. It provides a negative voltage from a single positive supply.

Neon Desk Lamp:

PC Board Layout Eases High Speed Transmission: 11/08/01 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit

Perimeter Monitor: Using a single cable such as speaker wire or doorbell cable, this circuit can be remotely positioned, for example, at the bottom of a garden or garage, and used to detect all sound in that area. The cable can be buried in a hosepipe or duct and is concealed out of sight. The mic is an ordinary dynamic mic insert and should be housed in a waterproof enclosure with the rest of the circuit.

Portable CD Player Kit: The hardware consists of a normal tape cassette fitted with a stereo cassette head. The heads signals are provided by a standard CD player. The power supply consists of an adjustable regulator connected to the cars cigarette lighter connector.

Pot Plant Power: All plants carry an electric charge relative to the ground. This charge is more or less constant regardless of the size of the plant - a kind of background voltage" in nature. This electric charge suffuses the entire plant, from its roots to its leaves and fruit. It was measured between a chrome-plated pin inserted into the plant (the positive terminal) and an iron spike driven into the ground (the negative terminal).

Power circuit terminates DDR DRAMs: 11/14/2002  EDN - Design Ideas / DDR (double-data-rate) SDRAMs find use in high-speed memory systems in workstations and servers. The memory ICs operate with 1.8 or 2.5V supply voltages and require a reference voltage equal to half the supply voltage (VREF=VDD/2). In addition, the logic outputs terminate with a resistor to the termination voltage, VTT, which equals and tracks VREF.

PreWarped Drive Signal Reduces Actuator Hysteresis Error : 02/18/02 Electronic Design - Ideas for Design / Many displacement transducers exhibit hysteresis in their response to drive signals. To observe this behavior, drive the actuator with a triangle wave while measuring the actuator response with a linear position transducer.

Quiz Game Circuit:

Refrigerator Door Alarm:

RISC µP implements fast FIR filter: 01/21/99 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit

Routine automates pattern/sequence detection: 05/16/2002  EDN - Design Ideas / Sequence detection is a common operation in many communication and security systems. Some good examples are HDLC-flag identification and signature analysis. As the complexity of the system increases, designing circuitry for sequence detection becomes tedious and laborious.

Routine yields fast bit reversing for DSP algorithms: 09/13/2001 EDN - Design Ideas / If you need efficient real-time performance in DSP applications, you need an efficient bit-reversing routine. For several FFT programs, data permutation can take 10 to 50% of the computation time, depending on the input-data dimensions and length.

RTTY Terminal unit:

Rules of thumb Aid in time constant Analysis: 11/06/97 EDN-Design Ideas

Several Nuclear Physics Related Circuits:

Simple FIFO provides data width conversion: 09/26/2002  EDN - Design Ideas / Many designs require FIFO elastic buffers to form a bridge between subsystems with different clock rates and access requirements. However, in some applications, you need FIFO buffers for data conversion.

Simple PIC16F84 Programmer:

Simple Technique Generates Precise HART Waveforms : 07/22/02 Electronic Design - Ideas for Design /  Designed to complement conventional 4- to 20-mA analog signaling, the Highway Addressable Remote Transducer (HART) protocol supports two-way digital communications for process measurement and control devices.

Single Phase Electronic Starter:

Single sideband Demodulator Covers the HF Band: 10/26/00 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit

Solar Cell Nicad Charger:

Soldering Technique Reduces PC Board Damage: 05/21/98 EDN-Design Ideas

Spectrum Analyzer & Equalizer Designs: for audio frequencies, article first appeared in the February1982 issue of Recording-engineer/producer magazine

Speller Effect Sign Display:

SSB AF Filter:

StateVariable Oscillator Suits Ratiometric Capacitive Sensors : 09/30/02 Electronic Design - Ideas for Design / Often, it's necessary for a sensor system to compute the ratio of two capacitors. Doing so re-duces the transducer's sensitivity to dielectric errors from such factors as temperature.

Static Electricity / Negative Ion Detector: This circuit relies upon the extra high input impedance of a FET, and also demonstrates the gate terminals sensitivity to changes in voltage.

Stud Sensor Automatic :

Supply uses AC to Generate 5V, Power on Reset : 05/16/2002  EDN - Design Ideas / The need often arises for a low-cost logic supply for powering microcontrollers and related circuitry in "white-goods" products, such as industrial controllers and sensors. These applications usually include 24 or 115V ac or higher levels of ac voltage for conversion to 3.3 or 5V dc.

T Volt Remote Control Blocker: this PDF file includes also some other funny circuits

Tandem hookups Enhance utility of DC / DC units: 01/02/97 EDN-Design Ideas

Tele Scope:

Temperature Monitor:

Transconductance amp gives oscillator reciprocal response: 04/17/03  EDN-Design Ideas / The circuit in Figure 1 is a variation on the familiar integrator/comparator triangle-wave oscillator, which you typically implement with two op amps. An integrator and a comparator connect in a positive-feedback loop; the comparator drives the integrator and vice versa. A fixed amount of hysteresis exists in the comparator, producing a triangle wave at the integrator's output.

Ultrasonic Dog Whistle:

Voice Storage Chips Talk to Each other: 11/05/98 EDN-Design Ideas

Whistle Detector: It uses digital techniques to measure and decode the input signal to detect a whistle, all using a 8-pin PIC device and a handful of analog components. This project is ideal for beginners wanting to try their hand a PIC programming!


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