Vacuum Tubes Valves
Musical & effects
Yagi Uda Antennas
Metal Detector Circuits
Liquid Sensing Circuits
Light Sensing Circuits
Voltage Detector Circuits
Air-Gas Detection Circuits
Human Sensing Circuits
RF & Radiation
Optical Sensing Circuits
Free Energy Circuits
AC to DC & DC to DC
Solar Cell Circuits
Micro Power Circuits
Switching Power Supplies
Light Laser LED
Digital to Analog
Analog to Digital
Data Bus Circuits
Voltage to Pulse
Current to Voltage
Frequency to Voltage
RF Converter Circuits
Sine to Square Wave
Voltage to Current
voltage to frequency
Period to Voltage
Video Wall circuits
TV Video Circuits
Motor Control Circuits
8051 / 8052
PCB CAD Software
Car bike Circuits
555 Timer Circuits
Remote Control Toy
H Bridge Circuit
DIY HV Variable Cap
DIY PMA alternator
Interconnection & Timing
Digital Signal Integrity
Digital & Bipolars
Sensors & Detectors
Regulated Power Supply
4 Band Resistor
5 Band resistor
6 Band resistor
Meter Counter Circuits
Soil Heater For Plants Circuit
A TDA1024 electronic thermostat senses soil temperature via thermistor R6. The circuit uses zero-crossing switching of the heater. The heater is made of elastic-coated steel wire. PI is used to set the temperature. The heater should have 2 or more resistance and operate from the 9-V transformer.
Telephone Line Tester Circuit
The telephone-line tester consists of nothing more than a meter (that`s used to measure line voltage in the on- and off-hook state), three resistors (one of which is variable), a pushbutton switch, and a modular telephone connector.
This circuit provides a linear increase of frequency of 10 Hz/Â°C over 0-100 Â°C and can thus be used with logic systems, including microprocessors. Temperature probes Ql Vbe changes 2 mV/Â°C. This transistor is incorporated in a constant current source circuit. Thus, a current proportional to temperature will be available to charge Cl. The...
This temperature controller operates as a pulse snatching device, which allows it to run at its own speed and tum on at the zero crossing of the line frequency. Zero crossing tum-on reduces the generation of line noise transients. TMOS Power FET, Ql, is used to tum on a heater. Temperature sensor D6 provides a de voltage proportional to...
The fan employed is one of the new electrostatic type which is very reliable, because it contains no wearing parts. These devices require high-voltage drive. When power is applied, the thermistor, located in the fan"s exhaust stream, is at a high value. This value unbalances the A3 amplifier driven bridge. Al receives no power and the fan...
Both of these converters use CMOS inverters. Figure 105-1A shows a free-running circuit having both the pulse duration and pulse pause dependent on temperature of the diode D8. It can be used where a synchronization between the converter and something else is not required. Figure 105-lB shows a one shot circuit that produces a pulse with its...
The ROMs or PROMs must have the correct code for converting the data from the NE5037 -used as address for the ROMs or PROMs-to the appropriate segment driver codes. The displayed amount could easily be converted to degrees Fahrenheit, Â°F, by the controller of (0-63 Â°temperature sensor) or through the (P) ROMs. When doing this, a third...
The DVM-to-temperature adapter is built around a single IC, National"s LMlO. That micropower IC contains a stable 0.2 V reference, a reference amplifier and a general-purpose op amp. The circuit is designed for a linear temperature range of 0 to 100Â°C (32 to 212Â°F). The 0.2-V reference and reference amplifier provide a stable,...
This oscillator circuit includes a quartz crystal that has a nominal resonant frequency of 262,144 Hz and is cut in the orientation that gives a large linear coefficient of frequency variation with the temperature. In this type of circuit, the oscillation frequency is controlled primarily by the crystal-as long as the gainbandwidth product is...
Temperature Controller With Defrost Cycle
This temperature controller has a range of -50 to +150Â°C and permits defrosting. R7, VR3, and R8
Transistor Sensor Temperature Measurer
Using the fact that the VRE of a transistor shifts 59.16 mV per decade of current at 25Â°C. This cons
The circuit switches the current to an electrical heater on and off to maintain the temperature of a room at 25 Â±0.5Â°C. The temperature sensor is a thermistor which provides a differential input (for reduced noise) to an operational amplifier. A 5 kilohm potentiometer is used to adjust the set point through a voltage divider; a value of 2.17...
Precision RTD signal conditioner
The circuit provides complete, linearized signal conditioning for a platinum RTD. This LTC1043 based circuit is considerably simpler than instrumentation or multi-amplifier based designs, and will operate form a single 5 V supply. Al serves as a voltage-controlled ground referred current source by differentially sensing the voltage across the...
Heater temperature controller
The circuit can control up to 6 kW of heating, with moderate gain, using a 25-amp triac (SC260D). Feedback is provided by the negative temperature co-efficient (NTC) thermistor, which is mounted adjacent to the environment being temperature controlled. The temperature set potentiometer is initially adjusted to the desired heating level. As the...
Digital temperature measuring
The output voltage of a thermocouple is converted into frequency measured by a digital frequency meter. The output thermocouple signal is proportional to the temperature difference between the hot junction and the thermostat kept at 0Â°C, it drives the voltage-to-frequency converter changing the analogue input signal into the output frequency...
This circuit has the CMOS IC doing double-duty performance. The first two inverters operate as a digital audio oscillator; the third operates as a low-gain linear audio amplifier. As the intensity of the light falling on photoresistor LDRl increases the oscillator's frequency increases; similarly, the illumination falling on photoresistor LDR2...
The low output impedance of a closed loop op amp gives ideal line-noise immunity, while the op amp's offset voltage drift provides a temperature sensor. Using the op amp in this way requires no external components and has the additional advantages of a hermetic package and unit-to-unit mechanical uniformity if replacement is ever required. The...
Zero voltage switch temperature control
The ' 'zero voltage switching'' technique is widely used to modulate heating and similar types of ac loads where the time constant associated with the load (tens of seconds to minutes) is sufficiently long to allow smooth proportional modulation by time ratio control, using one complete cycle of the ac input voltage as the minimum switching...
Dual over-under temperature monitor
This circuit is ideal for use as an over-under temperature monitor, where its dual output feature can be used to drive HIGH and LOW temperature-indicator lamps, relays, etc. Tl is a 6.3 volt filament transformer whose secondary winding is connected inside a four arm bridge. When the bridge is balanced, ac output is zero, and C5 (or C7) receives...
Temperature sensor and DVM interface
The DVM gives a direct indication of the temperature of the sensor in degrees Centigrade. The temperature sensor IC1 gives a nominal 1 Âµ per degree Kelvin which is converted to 10 mV per degree Kelvin by Rl and VR1. IC2 is a micropower, low input drift op amp with internal voltage reference and amplifier. The main op amp in IC1 is connected as...
An inexpensive electronic thermometer is capable of measuring temperatures over a range of from -30Â°F to +120Â°F. A diode-connected 2N3904 transistor used as the temperature sensor forms a voltage divider with Rl. As temperature increases, the voltage drop across the transistor changes by approximately -1.166 millivolts-perÂ°F. As a result, the...
Vegetable greenhouse temperature detection control circuit
Vegetable greenhouse temperature detection control circuit Greenhouses temperature detection control circuit, it is mainly by the
Thermostat controller integrated circuit schematic
As shown in Figure by the built-in temperature sensor to control the triac TC620 achieve temperature control. Adjustment circuit Rp1 and Rn
Thermostat controller integrated circuit schematic
As shown in Figure by the built-in temperature sensor to control the triac TC620 achieve .png">temperature control .
T-121 Temperature sensor circuit diagram (electronic thermometer)
T-121 temperature sensor electronic thermometer circuit diagram shown below
Thermocouple thermometer circuit
Circuit from the MAX1494 and thermocouple temperature measurement system as shown, MAX1494 termination of 1N GND 5-32. The use of an external temperature sensor (for example, DS75) and SCM can be done carry junction temperature compensation work. MAX1494 uses an external reference provided by the MAX6062 reference voltage +2. 048V is.
Thermocouple amplifier gain circuit
OP07 low drift (maximum voltage drift 30 FLV, maximum drift 0.6vV / aC), low noise (maximum 0.6 pLVp.P),
Thermocouple Amplifier circuit (CA3193)
The circuit needs 15 volts and uses a precision op amp CA3193 BiMOS to amplify the signal generated more than 500 times. Three 22-megohm resistors provide large-scale output if the thermocouple opens.
Avoid contact thermometer circuit
In order to prevent electric contact pressure thermometer contacts singeing failure, the best way is to work to improve the contacts, as shown in Fig. 11-60.
Manual thermostat circuit
Adjustment potentiometer RP, can change the TRIAC V conduction angle, to achieve tempering purposes.
Bimetal thermostat control one circuit
Use fluorescent starter bimetal can be prepared as a temperature sensing element, as the thermostatic control. Double metal sheet for temperature sensing element, the circuit is simple, easy to
Intelligent interface circuit and temperature sensor DS1620 SPI bus circuit
With a three-wire serial interface smart temperature sensors DS1620 and SPI bus interface circuit as shown below:
Frequency Meter Circuits
VU Meter Circuits
Ultrasonic distance finder circuit
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is measured. There are three main categories of distance measurement methods in use: a) By...
Simple Metal detector circuit with CD4030
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to find something potentially valuable, hidden a few centimeters below the soil. So many...
Fully automatic watering circuit for flower pots
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This circuit comes as a solution to this problem. Depending on humidity of the pot at...
Simple deep searching metal detector circuit
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the circuit of this metal detector, it is possible to detect a metal coin in depth of 90 to...
Sub-Harmonic Bass Converter for Electric Guitars
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound, such as filtering or distortion. Instead, a frequency division system produces outputs...
Echo Depth Sounding Sonar for Boats
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the calibration of the rope. This arrangement still exists in some yachts. The big...
100W HiFi Audio Amplifier Circuit
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power supply must be symmetrical so that no electrolytic capacitors are needed at the outlet....
Plant-Pot Water Level Indicator Circuit
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower. The circuit of the device is shown in Figure 2. The water detection is made from the bottom...
Analogue Sound Preasure dB-Meter Circuit
The best human ear can capture sounds from 20Hz to 20KHz. These limits are known to be the broadest that can exist. Normally the normal limits range from 100Hz to about 13KHz and depend on the age and health of the individual. We for our measurements and to have a good accuracy we will get the limits of 20Hz to 20KHz. A sound to be heard does...
DIY HV Variable Capacitor
DIY PMA Alternator Plans
Digital Signal Integrity