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Tesla Coil/H Volt Generator - This is a fun and useful circuit for demonstrating high frequency high voltge. It can produce up to about 30KV, depending on the transformer used. It is cheap and easy to make, thanks to the standard TV flyback transformer used. It can power LASERS (although I have never tried) , demonstrate St. Elmo's fire, and even cause a fluorescent bulb to light from as much as 2 feet away. __ Designed by Aaron Cake The "Miller engine" - Type 1 (Voltage Controlled) Solar Engine - This is a slightly more-sophisticated design based on a 1381* voltage discriminator. __ Designed by Wilf Rigter
The BEAM Stepper drive - The 74AC240 stepper driver works by alternately enabling each half of the buffer. Only one half can be enabled at a time. Let's assume that the top half of the driver is enabled. U1A & U1B along with R8, C1, and the input protection resistor R7 form a square wave oscillator. The outputs of U1A & U1B directly drive one coil of a bipolar stepper motor. __ Designed by Duane Johnson and Wilf Rigter
The dual slope-sampling solar engine - If you had time to experiment with the ALF type SE circuit you may have discovered some of its shortcomings with regard to a Power Smart Head adaptation. The problem is that HCMOS
gates are power hungry when used as SE voltage comparators when the analog input voltage is near the CMOS
switching threshold. If an HCMOS
gate is used without sampling, the chip supply current can be as high as 70mA with the comparator input voltage near the trigger threshold (Vcc / 2) . __ Designed by Wilf Rigter
The GBSE (gate boost solar engine) - The Gate Boost SE uses a 1381, a 2N7000 MOSFET and a 2N3906 with a unique voltage doubler to increase the voltage applied to the gate of the MOSFET. Normally the 2.6V output of a 1381C is barely able to turn on the 2N7000. As a result the "on resistance" of the MOSFET is high and much power is wasted. __ Designed by Wilf Rigter
The HC11 Controls the Stepper - Simple circuit with 16-pin Nitron chip 68HC908, easy analog setting, source code with ICC08. New s-record for 8-pin 68HC908QT2! __ Designed by Ludwig Orgler-Fachingenieur Elektrotechnik
The MicroPower Solar Engine - A 'micro power solar engine' has been a goal since my introduction to BEAM Robotics. I believe that if there wasn't one before, I there is one now. What I'm presenting to you looks very similar to one of the circuits found in Steven Bolt's web pages. As you will see, I made only minor changes to that design and not without help. __ Designed by Ken Huntington
The Miller solar engine - The Miller solar engine uses a 1381* voltage detector (a. k. a. , a voltage supervisor) IC to drive a voltage-based (type 1) solar engine. The 1381 is normally used to reset CPUs and Micros when the power supply drops too low for reliable operation. So 1381s detect and switch when the input voltage crosses the rated upper and lower threshold voltages. The upper- and lower-switching voltages are slightly overlapped so that the turn-on voltage is a few hundred mV above the turn-off voltage. This hysteresis keeps input noise (around the switching threshold) from resulting in multiple output cycles as the transition occurs. __ Contact: Eric Seale
The VTSE solar engine - The VTSE uses the popular 1381 chip and that is its main advantage. The potentiometer (or two fixed resistors) connects one leg between the output and input of the 1381 and the other leg to the supply voltage. These resistors acts like a voltage divider when the SE is off and the 1381 output is low. In that case, the voltage that appears at the 1381 input is determined by the ratio of the pot or the two resistors and is usually set for 2 times rated 1381 voltage. __ Designed by Wilf Rigter
The Vx2SE solar engine - The Vx2SE is a simple discrete voltage-doubling SE for driving an LED. If the load is a red or green LED, J1 is used together with just one red or green LED for threshold detection (no 1381) . For driving a blue LED use two green or red LEDs in series and may require a higher voltage (3V) solar cell. With 100uf capacitors the flash frequency is 2-3Hz and the R2 and R3 resistors may be omitted. With very large capacitors (0.01F and up) the frequency is much lower and the resistors can be optimized to stretch the LED "on" time. The Vx2 solar engines will self trigger but are also sensitive to a drop in light and will trigger from a shadow etc. __ Designed by Wilf Rigter
Thermal cooling fan controller - As we begin to enjoy those lazy hazy days of summer, the most important thing on most of our minds is how to keep cool during those hot days. For some of us that means turning up the old air conditioner and sipping on a nice cold glass of our favorite soft drink. However, we often forget about an equally important __ Designed by Radio Amateur Society of Norwich
Thermal Fan Controller - The controller uses one or more ordinary silicon diodes as a sensor, and uses a cheap opamp as the amplifier. I designed this circuit to use 12V computer fans, as these are now very easy to get cheaply. These fans typically draw about 200mA when running, so a small power transistor will be fine as the switch. I used a BD140 (1A, 6.5W) , but almost anything you have to hand will work just as well. __ Designed by Rod Elliott ESP
Thermofan to Keep Your Amp Cool - Use a 12V computer fan to cool your amp. Uses diode temperature sensor f __ Designed by Rod Elliott ESP
Thermostat for 12v Cooling Fan - 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 . . . Hobby Circuit designed by Dave Johnson P.E.-February, 2011
Three-Phase Motor Driver Prevents Stall - 01/05/95 EDN-Design Ideas - The circuit in Fig 1 drives a small 24V, 50-Hz motor at about 30 to 40 Hz for use as a chopper motor. The best starting speed for the motor is about half the final running speed. Therefore, the circuit uses an intermediate speed to prevent a stall condition. The circuit uses IC1Ato count down two cycles after the selection of the intermediate speed. IC1B's Johnson divide-by-three counter and IC2's gates generate the 1208 phase angle Design by PM Kirkby, Crumpsall Electronics, Surrey, England
Time Delay Relay - A time delay relay is a relay that stays on for a certain amount of time once activated. This time delay relay is made up of a simple adjustable timer circuit which controls the actual relay. The time is adjustable from 0 to about 20 seconds with the parts specified. The current capacity of the circuit is only limited by what kind of relay you decide to use __ Designed by Aaron Cake
Time Delay Relay II - When activated by pressing a button, this time delay relay will activate a load after a specified amount of time. This time is adjustable to whatever you want simply by changing the value of a resistor and/or capacitor. The current capacity of the circuit is only limited by what kind of relay you decide to use __ Designed by Aaron Cake
Tiny Robot - Recently many kind of robot contests have being opened and some interesting reports of the challenge are found on the web. The Line Following is a kind of the robot contests to vie running speed on the line. I build a tiny line following robot which can run on the desk, moving the key board aside will do. It is for only a personal toy reduced i __ Designed by The Electronic Lives Manufacturing-presented Chan
Touch Switch using 4011 CMOS
NAND Gate IC - A touch switch is a switch that is turned on and off by touching a wire contact, instead of flicking a lever like a regular switch. Touch switches have no mechanical parts to wear out, so they last a lot longer than regular switches. Touch switches can be used in places where regular switches would not last, such as wet or very dusty areas __ Designed by Aaron Cake
Transformerless Power Supply - I have received a few emails asking for a transformerless power supply. Here is such a supply. This supply uses no heavy step down transformer and has an extremely low parts count. The circuit can be built very small and can supply small currents for small projects. The major downfall of this supply is that it is not isolated from the AC line and can only supply small currents __ Designed by Aaron Cake
Tritium - Charge Rate-Controlled Solar Engine: The Tritium circuit was the first (to my knowledge) type 3 SE. As such, it is quite experimental, and should be regarded as a prototype rather than the 'state of the art'! Nevertheless, it does function reasonably well, and in some circumstances outperforms other solar engines such as the Freds that I have lying around. __ Designed by Wilf Rigter
Two Basic Motor Speed Controllers - Here are two simple 12V DC motor speed controllers that can be built for just a few dollars. They exploit the fact that the rotational speed of a DC motor is directly proportional to the mean value of its supply voltage. The first circuit shows how variable voltage speed control can be obtained via a
Two Components Drive Stepper Motor - EDN-Design Ideas - 01/19/95 The extremely simple circuit in Fig 1 drives a stepper motor directly from 120V ac, 60 Hz. Usually you need switched-dc voltages to drive a stepper motor. But a stepper motor will run off ac lines if you introduce a 90° phase shift between the voltages applied to the motor's two windings. Design by Carl Spearow, Basler Electric,m Highland, IL
Two Pushbutton Motor Controller - Two small pushbutton switches, a few diodes and two relays form a method to control on/off power to a brush motor as well as the motor direction. The circuit was originally designed for a motorized lifting platform. . . Circuit by David Johnson P.E.-September, 2005
Two Wire Stepper Motor Positioner - A simple and inexpensive way to remotely rotate a display or object is with a positioner that uses a stepper motor to rotate it. The motor is driven by a circuit mounted near the motor and by a control circuit at a remote location. __ Golab.com
Two-button control for dangerous machines - Two button control systems are used on dangerous industrial machines in order to protect the operator’s hands. Just for hobby I made a circuit that turns on a relay by pressing two buttons simultaneously. __ Designed by Andrea-Central Italy
Type 1 Solar Engine-voltage controlled trigger - Voltage controlled trigger - This is by far the predominant form of solar engine, since they are "efficient enough" for most uses, and pretty simple to build. __ Contact: Eric Seale
Type 2-Solar Engine-time controlled trigger - Time controlled trigger - These aren't terribly efficient, but are handy for 'bots that need activity at specific times. __ Contact: Eric Seale
Type 3-Solar Engine-charge curve differentiated - Charge curve differentiated (i. e. , it triggers when the charge rate of the capacitors slow down) -- These are theoretically the most efficient, though type 3 designs are still in their infancy. __ Contact: Eric Seale |
