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
Bird Feeder Monitor Circuit
The first amplifier circuit is a bird phone. In this circuit, the electret mike (MIC1) is mounted in the neck of a large plastic funnel. The amplifier, built around an MC34119 (which is available from D.C. Electronics, P.O. Box 3203, Scottsdale, AZ 85271-3203; Tel. 800-467-7736, and elsewhere), is then placed outside of the funnel with the...
Electronic Thermostat Circuit
A diode, such as a IN4148, has a typical -2m V/C temperature coefficient at a 1 mA diode current. Ql and Q2 form a constant current source. D1 is the temperature sensor. ICl-a and -b are dc amplifiers, with ICl-c a temperature reference voltage supply. ICl-d is a comparator with variable hysteresis. R14, R15, and R16 are chosen depending on the...
Reflex Timer Circuit
This timer circuit uses a 555 IC timer and three 74LS193 counters to drive an LED display. SI is activated by one person, who turns on piezo buzzer BZ1 via Ql and also starts the clock; SI is activated by the other person being timed.
Tele Timer Circuit
The circuit is built around a 555 oscillator/ timer. The circuit provides two time periods. The long-running time period is adjustable from about 1 to 10 minutes, and the short time period is preset to about three seconds. Here`s how the dual timer operates. When the power is switched on, G2 begins to charge through R3, Rl, Dl, and R4 to start...
Count Down Timer Circuit
With switch SI in the off position, as shown, battery voltage is applied across timing-capacitor CI, which stays charged while the rest of the circuitry has no power supplied to it.
The time base is first selected with Sl set for seconds or minutes, then units 0-99 are selected on the two thumbwheel switches S4 and S5. Finally, switch S2 is depressed to start the timer. Simultaneously, the quartz crystal-controlled divider circuits are reset, the ICM7250 is triggered and counting begins.
Self Retriggering Timed Generator Circuit
When power is first applied to the circuit, 02 begins to charge via LED1, R3, and R4. When the voltage across C2 reaches Ul`s input trigger level, the output of Ul at pin 6 goes positive for a period that is determined by the values of and it! r That turns Ql on, discharging 02 through D1 and Ql. At the end of the set period, the output of Ul...
After one cycle of operation, SCR 1 will be on, and a low value of voltage is applied to the UJT emitter circuit, interrupting the tuning function. When pushbutton SI is pushed, or a positive going pulse is applied at point A, SCR 2 will turn on, and SCR 1 will be turned off by commutating capacitor CC. With SCR 1 off, the supply voltage will be...
Long duration timer
The time circuit can provide a time delay of up to 20 minutes. The circuit is a standard relaxation oscillator with a FET current source in which resistor Rl is used to provide reverse bias on the gate-to-source of the JFET. This turns the JFET off and increases the charging time of Cl.
Precision time-countdown timer
The circuit uses an ICM7213 precision one minute/one second timebase generator using a 4.1943 MHz crystal for generating pulses counted by an ICM7217B. The thumbwheel switches allow a starting time to be entered into the counter for a preset-countdown type timer, and allow the register to be set for compare functions. For instance, to make a...
Microprocessor programmable interval timer
The microprocessor sends out an 8-bit binary code on its 8-bit I/O bus (the binary value needed to program the ICM7240), followed by four WRITE pulses into the CD4017B decade counter. The first pulse resets the 8-bit latch, the second strobes the binary value into the 8-bit latch, the third triggers the ICM7240 to begin its timing cycle and the...
Novel circuit diagram of the timer switch
Novel timing switch circuit in addition to a general timing circuit "Variable Timing" adjustment function, also has a
Op amp F003 composition of automatic exposure timer circuit
As shown in Figure II F003 is versatile photographic constituent operational amplifier amplifying automatic timer circuit. Operational amplifier A1 composition integrator
FM by a timer ME555 circuit
The figure is composed by a NE555 and other withered frequency circuit by changing the self-excited multivibrator NE555 charging current to frequency modulation. The circuit is VT1 and VT2 constitute a current mirror circuit, the charging
1 hour LM122 timer circuit
As shown in Figure 1 hour using a LM122 timer circuit. Start of the circuit, reset and stop halfway, etc. are converted by the switching operation. Figure, S1 to start timing when the timer is started, then this switch has no effect. S2 is centrally located in
555 timer circuit diagram of a group of anti-jamming
555 in the use of time-based circuit design from the timer circuit, generally will be 555 monostable circuit is connected, so connected so that the circuit design is simple, re
555 timer circuit temperature sensor temperature
555 timer is a combination of analog and digital functions in scale integrated devices. Usually made with bipolar process called 555, with the CMOS process is referred to 7555,
MP1826 by the LM567 and precision timer circuit
A precision shown by the LM567 timer circuit MPI826 constructed and where LM567 used as a dual-band oscillator. MP1826 acts as a divider in the circuit, the output signal by di
Universal multi-function alarm and timer circuit 555
As shown for the general multi-function alarm and timing circuitry. The timing of the circuit can range from 5 minutes to 3 hours. Timing components C2, VD1 and VT1 composition
Simple timer circuit MC14541
As shown in FIG MC14541 constituted by a simple timing circuit. The circuit uses IC MC14541 constitute a simple timing circuit. Press the parameter map, the timing for 3 hours,
lm567-mp1826 precision timer circuit diagram
As shown in FIG, MP1826 in the circuit as a multi-stage divider. LM567 is the frequency demodulation circuit, the circuit as a dual-band oscillator which generates the desired
Use of one hour LM122 timer circuit
As shown in Figure 1 hour using a LM122 timer circuit. Start of the circuit, reset and stop halfway, etc. are converted by the switching operation. Figure, S1 to start timing w
4 hours AC power timer circuit 555 BH4024
As shown in Figure 4 hours AC timing circuit. In this circuit, BH4024 is 7 serial binary counter/divider 555 time base circuit. AN is timed touch of a button. Each press AN tim
Low power timer switch
As shown, the timing circuit due to the installation of the electronic switch by the F1, F2 and VT1 composed of quiescent current can be reduced to 555 l ~ 2 A. When the power
Sequence timer circuit diagram of 555 chips
By 0.001 F the first half of the coupling capacitor 556 pairs timer output is supplied to the second half of the input given individual delay equal to the sum of the total dela
Car or room timer alarm circuit diagram
Circuit photoelectric switch S1 is gated or luggage room light control switch. A point is in its closed operating voltage is positive. If S2 is closed, regardless of whether or
Thyristor controlled motor reversing circuit a timer
Circuit shown in Figure 3-69. It applies to require frequent timing control motor reversing operation of the occasion. Drawing, thyristor Vl, V2 and V7, vs used as a positive c
Li-ion Battery Charger
The features of the MC68HC908QY/QT include a 4-channel Analog to Digital Converter and Timer module which can be set to generate PWM signals. This feature makes this MCU suitable for application such as a single cell Li-ion battery charger. The MC68HC908QY/QT is available in several packages with different memory size to fit into various...
Motorcycle Alarm Number 2
This circuit features an intermittent siren output and automatic reset. It can be operated manually using a key-switch or a hidden switch; but it can also be wired to set itself automatically when you turn-off the ignition. By adding external relays you can immobilize the bike, flash the lights etc. Ron has used my Asymmetric Timer as the...
darkroom timer with PIC 16F84A
I tried to design a timer that would do everything it needed to do but with the smallest number of pieces and simplest mode of operation. It only needs the PIC, a four digit LED display, one other IC, a resistor network, one pushbutton switch and a capacitor. It can run on batteries if you use a solid state relay to turn the exposure light on...
PC Controlled Voltage or Current Source
This project was begun as a means to charge and cycle NiCad batteries but has become a versatile tool for experiments requiring either a controlled voltage up to +30V and/or a current of +/- 2.5 Amps. If all you want to do is charge and recycle NiCad batteries, then, with hindsight, I`d advise you to buy one of the commerical units available....
This simple circuit is a good solution to the powering a dual supply op amp from a single battery problem. The circuit simply takes a positive voltage and inverts it. It uses only one 555 timer and a few other passive components, so it doesn`t add much in the way of size and cost to a project.
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