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Transistor Circuits
Transistors:  #'s - C    D - I     J - O     P - S     T - Z

Last Updated: October 18, 2017 05:04 AM

Circuits Designed by Dave Johnson, P.E. :
300v Peak to Peak Signal Generator -  This circuit converts a square wave signal to a +-150 volt output signal with fast 100nS rise and fall times. . . Circuit by David Johnson P.E.-June, 2000

AC/DC relay from Charge Coupled MOSFET -  This circuit acts as an AC/DC relay with a rating up to 50 volts peak and up to 10 amps of current.  The differential oscillator supplies voltage to the gates of the two FETs with good isolation will drawing only 1.5ma of current . . . Hobby Circuit designed by David Johnson P.E.-October, 2005

Astable Multivibrator with Very Low Power -  This classic circuit draws only 200 nanoamps from a 1.5v supply . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000

Bi-Directional Charge Coupled Powers MOSFET Relay -  The circuit uses an inexpensive C-MOS inverter package and a few small capacitors to drive two power MOS transistors from a 12v to 15v supply.  Since the coupling capacitor values used to drive the FETs are small, the leakage current from the power line . . . Hobby Circuit designed by David Johnson P.E.-June, 2000

characteristics of CMOS Logic Inverter Amplifiers -  This chart shows some of the measured characteristics of three different unbuffered CMOS logic gates, used as voltage amplifiers . . . Hobby Circuit designed by David Johnson P.E.-February, 2002

Charge Coupled Bi-Directional Power MOSFET Relay -  The circuit uses an inexpensive C-MOS inverter package and a few small capacitors to drive two power MOS transistors from a 12v to 15v supply.  Since the coupling capacitor values used to drive the FETs are small, the leakage current from the power line. . . Circuit by David A. Johnson P.E.-June, 2000

Charge Coupled MOSFET Relay #2 -  This circuit acts as an AC/DC relay with a rating up to 50 volts peak and up to 10 amps of current.  The differential oscillator supplies voltage to the gates of the two FETs with good isolation will drawing only 1.5ma of current. . . Circuit by David A. Johnson P.E.-October, 2005

Charge Pump Efficiently Divides Supply Voltage  -  This circuit uses a few FETs and logic devices to down convert a DC voltage to about one half its value. . . Circuit by David Johnson P.E.-July, 2000

Circuit Protects from Battery Polarity Reversal -  This simple circuit can protect a sensitive electronic circuit from an accidental connection of a battery with a reversed polarity.  The N-channel FET connects the electronic device to the battery only when the polarity is correct.  The circuit shown was. . . Circuit by Dave Johnson P.E.-March, 2002

CMOS Logic Inverter Amplifier characteristics -  This chart shows some of the measured characteristics of three different unbuffered CMOS logic gates, used as voltage amplifiers. . . Circuit by Dave Johnson P.E.-February, 2002

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

 
 

A 12 volt Inverter-Very Basic type -  This circuit will provide a fairly stable "Square Wave" Output Voltage.  Frequency of operation is Mainly determined by the 220 uF Feedback Caps.  Currently about 60 Hz.  Various "off the shelf" transformers can be used. __ Designed by G.L. Chemelec

A better MOSFET H Bridge Schematic -  Schematic only - no circuit desciption included __ Designed by Eugene Blanchard

A Simple Circuit Inverter -  This circuit will provide a fairly stable "Square Wave" Output Voltage.  Frequency of operation is Mainly determined by the 220 uF Feedback Caps.  Currently about 60 Hz.  Various "off the shelf" transformers can be used. __ Designed by G.L. Chemelec

A-4 Small Transistor Alarm Circuits -  Battery-Powered Alarm Circuits:  This is a selection of simple self-contained transistor based alarm circuits - complete with photographs.  They are designed around the Complementary Latch.  All may be triggered by both normally-open and normally-closed switches.  They have a very low standby current - and are ideal for battery operation.  __ Designed by Ron J.

AC/DC relay from Charge Coupled MOSFET -  This circuit acts as an AC/DC relay with a rating up to 50 volts peak and up to 10 amps of current.  The differential oscillator supplies voltage to the gates of the two FETs with good isolation will drawing only 1.5ma of current . . . Hobby Circuit designed by David Johnson P.E.-October, 2005

Active Mixer Design using the NE25139 Dual Gate MESFET 11/24/97  -  App Note  Doc #903__ California Eastern Laboratories

Advanced Polarity Protection with MOSFETs -  Advanced Power Switching and Polarity Protection for Effects __ Designed by 1999 R.G. Keen

AF power amp Design -  Several Circuits, be sure to scroll down.  First up is quasi-complementary amplifier.  Unusual to see in 2014, but great fodder for learning what goes on in a PA.  After making, debugging and analyzing these circuits, I felt humbled about how little I consider AC signal phase in addition to the easier concepts of amplitude and frequency during my AC signal analysis. __ Contact Vasily Ivanenko

Ampli MOSFET -  DiY high power MOSFET amplifier200 Wrms 8 ohms -350 Wrms4 ohms / __ Designed by Edwin Paij

Amplify & Shift EPAD MOSFET Output with an Operational Amplifier -  Circuit ideas for Designers App Note__ Advanced Linear Devices, Inc

Another Simple Circuit FM Transmitter -  Here is the schematic, PC board pattern, and parts placement for a low powered FM transmitter.  The range of the transmitter when running at 9V is about 300 feet.  Running it from 12V increases the range to about 400 feet.  This
transmitter should not be used as a room or telephone bug.   __ Designed by Kamran Ahmed-UK

Astable Multivibrator with Very Low Power -  This classic circuit draws only 200 nanoamps from a 1.5v supply . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000

Avago Tech Note: Driving & protecting inverter IGBTs -  EDN Design Ideas:  06/12/2014     A special purpose optocoupler can solve your iGBT gate-drive and fault-feedback needs __ Circuit Design

Basic EPAD MOSFET Connection with Current Source Drive -  Circuit ideas for Designers App Note__ Advanced Linear Devices, Inc

Basic MOSFET/ EPAD MOSFET Inverter -  Circuit ideas for Designers App Note__ Advanced Linear Devices, Inc

Basic MOSFET/EPAD MOSFET Diode-Connected  -  Circuit ideas for Designers App Note__ Advanced Linear Devices, Inc

Better MOSFET H Bridge -  Schematic only - no circuit desciption included __ Designed by Eugene Blanchard

Bi-Directional Charge Coupled Powers MOSFET Relay -  The circuit uses an inexpensive C-MOS inverter package and a few small capacitors to drive two power MOS transistors from a 12v to 15v supply.  Since the coupling capacitor values used to drive the FETs are small, the leakage current from the power line . . . Hobby Circuit designed by David Johnson P.E.-June, 2000

Bi-Directional Level Translator -  You often need to convert a logic signal from one power-supply voltage to another.  This conversion is a relatively simple task, unless the signal happens to be bidirectional.  Serial buses such as Access.  Bus, i2C, and SBI use bidire�Ψt into __ Designed by Jim Hagerman, Nokia Mobile Phones, San Diego, CA

Bipolar Transistor Audio Preamplifiers -  Before attempting to design a transistor amplifier circuit, it is necessary to acquaint ourselves with some very important design equations.  The most commonly used design equations are listed to the right to help us with our effort.   __ Designed by Mike Martell-N1HFX

Bipolar transistor boosts switcher's current by 12 times -  05/24/01 EDN Design Ideas:  The circuit in Figure 1 uses a minimal number of external parts to raise the maximum output current of a 0.5A buck switching-regulator IC to more than 6A.  The circuit accommodates input voltages of 15 to 60V and delivers output voltages of 3.3, 5, or 12V, depending on your choice of IC PDf has several circuits, scroll to find this one __ Circuit Design by Wayne Rewinkel, National Semiconductor Corp, Santa Clara, CA

Bit Reverser Scrambles Data for FFT -  03/02/95 EDN Design Ideas:  The hardware bit-reverse and linear-address generator in Fig 1a scrambles a time-domain digital N-sample record.  The circuit is primarily meant to scramble data before taking a real-time butterfly FFT and can follow a formerly published EDN-Design ideas ("DAC and P implement hardware window generator, " March 31, 1994, pg 58). __ Circuit Design by Alan Land, CRS Electronics, Pittsburgh, PA

Body diodes simplify UPS & energy recoverys -  EDN Design Ideas:  01/02/2017    This design idea illustrates a way to make use of MOSFETs parasitic body diodes in a power circuit that can be used in UPS and energy-recovery (e.g., regenerative braking) designs.  When the Mode input  is high, the circuit acts as a bridge rectifier.  The bridge consists of diodes D1, D2, and the body diodes of MOSFETs Q1 & Q2.  in this mode, Q1 & Q2 are off and Q3 is on, enabling DC output U1. __ Circuit Design by Peter Demchenko

Build a 200W MOSFET Amplifier Module -  A compact audio powerhouse ideal for guitar or PA work or for use as a general-purpose subwoofer or hifI amplifier.__ SiliconChip

Build an Op Amp with Three Discrete Transistors -  12/01/11  EDN Design Ideas:  This simple ac-coupled design inverts, runs off a single supply, and is self-biasing - You can use three discrete transistors to build an operational amplifier with an open-loop gain greater than 1 million (Figure 1).  You bias the output at approximately one-half the supply voltage using the combined voltage drops across zener diode D1, the emitter-base voltage of input transistor Q1, and the 1V drop across 1-MΩ feedback resistor R2.   __ Circuit Design by Lyle Russell Williams, St Charles, MO

Cascode MOSFET increases boost regulator's input- & output-voltage ranges -  09/01/05 EDN Design Ideas:  Simple enhancement extends range of both side as of regulator __ Circuit Design by Scot Lester, Texas Instruments, Dallas, TX

characteristics of CMOS Logic Inverter Amplifiers -  This chart shows some of the measured characteristics of three different unbuffered CMOS logic gates, used as voltage amplifiers . . . Hobby Circuit designed by David Johnson P.E.-February, 2002

Charge Coupled Bi-Directional Power MOSFET Relay -  The circuit uses an inexpensive C-MOS inverter package and a few small capacitors to drive two power MOS transistors from a 12v to 15v supply.  Since the coupling capacitor values used to drive the FETs are small, the leakage current from the power line. . . Circuit by David A. Johnson P.E.-June, 2000

Charge Coupled MOSFET Relay #2 -  This circuit acts as an AC/DC relay with a rating up to 50 volts peak and up to 10 amps of current.  The differential oscillator supplies voltage to the gates of the two FETs with good isolation will drawing only 1.5ma of current. . . Circuit by David A. Johnson P.E.-October, 2005

Charge Pump Efficiently Divides Supply Voltage  -  This circuit uses a few FETs and logic devices to down convert a DC voltage to about one half its value. . . Circuit by David Johnson P.E.-July, 2000

Cheap pushbutton replaces rotary switch -  26-Oct-00 EDN Design Ideas:  The problem of setting any one of four modes of aC-operated process has a straightforward solution  Have the C check the states of some 4 bits of aC.    __ Circuit Design by Abel Raynus, Armatron International Inc, Melrose, MA

Circuit Detects Current Pulse -  01/06/94 EDN Design Ideas:  The pulse detector provide as a visible indication of positive and negative current pulses.  The pulses amplitudes can vary from20 to150 mA.  The pulses durations can range from10 to40 msec, and their repetition rate can span40 to180 pulses/minute __ Circuit Design by Richard McGillivray, Grey Bruce Regional Health Centre, Owen Sound, Ontario, Canada

Circuit Lets You Characterize JFETs -  04/06/12  EDN Design Ideas:  Measure the pinch-off voltage VP and zero-bias drain current iDSS to select matched pairs of JFETs.   __ Circuit Design by John Fattaruso, Dallas, TX

Circuit optimizes PhotoTransistor Bandwidth -  04/09/98 EDN Design Ideas:  (several circuits included, scroll the find this one) A simple circuit can improve the dynamic performance of a phototransistor for use in low- to medium-speed applications as fast as 100 kbps, such as optical isolation of an RS-232C serial line (Figure 1).  in low-cost applications __ Circuit Design by David Magliocco, CDPI, Scientrier, France

Circuit Protects from Battery Polarity Reversal -  This simple circuit can protect a sensitive electronic circuit from an accidental connection of a battery with a reversed polarity.  The N-channel FET connects the electronic device to the battery only when the polarity is correct.  The circuit shown was. . . Circuit by Dave Johnson P.E.-March, 2002

Circuit provides ISFET-sensor bias -  10-Jun-04 EDN Design Ideas:  iSFETs (ion-sensitive field-effect transistors] are useful for measuring the acidity of fluids.  Accurate measurements require that the iSFET's bias conditions (iD and VDS] be held constant while the gate is exposed to the fluid under __ Circuit Design by Brian Harrington, Analog Devices, Wilmington, MA

Circuit reduces negative-voltage stresses on control IC -  04/18/02 EDN Design Ideas:  in a synchronous, buck switching power supply, the two FETS and the output inductor meet at the phase node (Figure 1).  The phase node often connects directly to the control IC .  The voltage on this node swings from the input voltage to some voltage lower than ground.  if the voltage goes too far below ground, the ESD structures or other circuitry within the control IC can become forward-bia __ Circuit Design by Michael Day, Texas Instruments Inc, Dallas, TX

CMOS Buffer Delivers Precise Current Pulse -  12/08/94 EDN Design Ideas:  The circuit in Fig 1 delivers stable, fast-settling reference-current pulses.  You can use the circuit in systems employing A/D, D/A, or V/F converters.  Digital input pulses, VP, connect to IC 3B, a 74AC240 buffer.  The 5.00V reference, IC 1, constrains IC 3B's output, VR, to either VREF or0V.  IC 3B's rise and fall times are <3 nsec __ Circuit Design by Hartmut Henkel, Consultant, Kriftel, Germany

CMOS DACs Act as Digitally Controlled Voltage Dividers -  06/26/08  EDN Design Ideas:  You can employ a DAC to operate as a digitally programmable resistor from a single supply __ Circuit Design by John Wynne and Liam Riordan, Analog Devices, Limerick, Ireland

CMOS Gate Implements Reverse Phase Control -  05/21/98 EDN Design Ideas:  (FILE has severa circuits, scroll down) The circuit in Figure 1 implements a "reverse" phase control, using only a single CMOS 4001 quad NOR gate.  The circuit is known as a reverse phase control because, unlike with common TRIAC or SCR controls, conduction begins at the zero crossing of the ac sine wave.  Timing of the turn-off point __ Circuit Design by JC Johnson, Lithonia Lighting, Decatur, GA

CMOS hex inverter generates low-distortion sine waves -  06/09/05  EDN Design Ideas:  Audio signal source uses hex inverter and handful of passives __ Circuit Design by Al Dutcher, West Deptford, NJ

CMOS IC Makes Low-Cost Digital Potentiometer -  01/18/96 EDN Design Ideas:  A growing trend in the design of electronic equipment is to replace analog knobs used to increase or reduce a continuous signal (such as volume or brightness]with "up" and "down" keys.  However, replacing a low-cost analog potentio __ Circuit Design by Jose Carlos Cossio, Santander, Spain

CMOS Latches Relays -  11/18/10 EDN Design Ideas:  A driver circuit take pulses and sets relays.  [Design ideas - by JC Maillet, Gabriola island, BC Canada __ Circuit Design by JC Maillet, Gabriola Island, BC Canada

CMOS Logic Inverter Amplifier characteristics -  This chart shows some of the measured characteristics of three different unbuffered CMOS logic gates, used as voltage amplifiers. . . Circuit by Dave Johnson P.E.-February, 2002

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Transistors:  #'s - C    D - I     J - O     P - S     T - Z

 


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