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4 Band Resistor
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RF Receiver Circuits
RF Receiver Circuits
DF data transmission module and the super-regenerative receiver module
DF data transmission module operates at 315MHz, the use of surface acoustic wave resonator SAW frequency stabilization, high frequency stability. When the ambient temperature i
The F â€” V input frequency is locked to the V â€” F output because the LTClG43's clock is common to both sections. The F â€” V's reference is used as one input of the multiplier, while the V â€” F furnishes the other.
The alarm plugs into the earphone jack on a receiver. Then when a signal (normally fed to the headphones) is detected and applied to the gate of SCR1, it conducts, sounding whatever alarm is connected to SOI. The signaling device can be an audible alarm or a lamp.
CW signal processor
This circuit provides interferenced rejection for the CW operator. The 567 phase-locked loop is configured to respond to tones from 500 to 1100 Hz. The Schmitt trigger reduces the weighting effect caused by the output of the PLL remaining low after removal of the audio signal. Ten to 15 millivolts of audio activate the circuit
FM carrier current remote speaker system
High quality, noise free, wireless FM transmitter/receiver operates over standard power lines. Complete system is suitable for high-quality transmission of speech or music, and will operate from any ac outlet anywhere on a one-acre home site. Frequency response is 20-20, 000 Hz and THD is under Transmission distance along a power line is at...
Carrier current receiver
60 kHz transformer consists of a 18 x 11mm ungapped pot core (Siemens, Fer-rocube, etc), utilizing magnetics incorporated type "F" material wound with SOV2 turns of No5 wire for the secondary and turns for the primary
Broadband frequency doubler
This circuit will double low-level signals with low distortion. The value of C should be chosen for low reactance at the operating frequency. Signal level at the carrier input must be less than 25 mV peak to maintain operation in the linear region of the switching differential amplifier. Levels to 50 mV peak may be used with some distortion of...
Simple LF converter
This converter allows coverage from 25 kHz up to 500 kHz. Use short coax from the converter to receiver antenna input
Cmos line receiver
The trip point is set half way between the supplies by Rl and R2; R3 provides over 200 mV of hysteresis to increase noise immunity. Maximum frequency of operation is about 300 kHz. If response to TTL levels is desired, change R2 to 39 K
This converter uses a low-pass filter instead of the usual tuned circuit so the only tuning required is with the receiver. The dual-gate MOSFET and FET used in the mixer and oscillator aren"t critical. Any crystal having a frequency compatible with the receiver tuning range may be used. For example, with a 3500 kHz crystal, 3500 kHz on the...
The decision to use either AM, narrowband FM Oess than 15kHz), or wideband FM (greater than 30 kHz) depends on the application. For the transmission of music, FM is better because it has greater noise immunity. For speech or other noncritical applications, AM may be satisfactory. Our transmitter permits either mode by switch selection. Audio...
Input signals from the power line are coupled through C23 and R19 to the input filter network. C23 must be rated at 600 volts. Switch 52 is used as an attenuator. Components C2 through C7, L1 through L3, R1, and R20 form a triple-tuned bandpass filter having a passband from 220-340 kHz. Signals from the filter are fed to an MC1350P gain block...
The AM Tuned Radio Frequency (TRF) receiver, has a sensitivity of about 1 m V at tbe input for an audio output of "iz W. Capacitor C22 couples audio signals from the power line to the PC board-it must be rated at 600 Vdc. R8 will cause F1 to blow, if C22 shorts. The signal from C22 goes to a tuned network (C1 through C5, Ll, and L2) that has...
In the 100-kHz application from left to right, the coupling network feeds into the receiver ~section on the bottom of the chip. (The external components are summarized later.) The receive data output is pulled up via RPuLL ~ 10 K!l. A minimum current of 10 mA sets the voltage drop across RpuLLÂ· Another voltage supply, VLoGJc, is shown if the...
Among the signals below 550 kHz are maritime mobile, distress, radio beacons, aircraft weather, European Longwave-AM broadcast, and point-to-point communications. The low-frequency converter converts the 10 to 500kHz LW range to a 1010 to 1550kHz MW range, by adding 1000kHz to all received signals. Radio calibration is unnecessary because...
The unit consists of rlamplifier Q1, local oscillatorQ2, and mixer Q3. The two bands are covered without a bandswitch by using an i-f or 3.5 MHz. The oscillator range is 7.5 to 14.5 MHz. Incoming signals from 4 to 11 MHz are mixed with the oscillator to produce the 3.5-MHz i-f. Signals from 11 to 18 MHz are mixed with the oscillator to also...
The NE602, U1, contains oscillator and mixer stages. The mixer combines the oscillator signal with the input rf signal to produce signals whose frequencies are the sum and difference of the input frequencies. For example, a 7.5-MHz signal is picked up by the antenna and mixes with the 8.5-MHz oscillator frequency. The difference between those...
This receiver is capable of better than 1.5 p, VIHF sensitivity and uses MOSFET front-end circuitry with varactors to eliminate conventional bulky tuning capacitors. It also features high dynamic range, ceramic i-f filters requiring no alignment, and a quadrature-type detector with excellent limiting and AM rejection capability.
The local oscillator is crystal-controlled and the i-f swing is hardly compressed. The deviation of the transmitted carrier frequency, because of modulation, must therefore be limited to prevent severe distortion of the demodulated audio signal. The component values result in an i-f of 4.5 kHz and an i-f bandwidth of 5kHz. If the i-f is...
The various signal frequencies are obtained for an incoming carrier centered at 49.86 MHz. The receiver employs double conversion, with i-fs at 10.7 MHz and 455kHz. Ceramic filters are used in both i-fs for selectivity and reduced"coil count. A quadrature detector is used to recover the baseband data, and an integrator and Schmitt trigger are...
This circuit is configured for the 80m band. The 365-pF, broadcast-band variable capacitor should have a vernier drive with a six-to-one ratio, which makes tuning easier by separating the stations on the dial. A good antenna and ground are also recommended.
When digital data is transmitted over long lines (longer than 1 meter), proper transfer is often disturbed by the parasitic effects of ground level shifts and ground loops, as well as by extraneous noise picked up along the way. An optocoupler, such as the HilL, combining galvanic isolation to minimize ground loop currents and their...
Visual Cw Offset Indicator
An NE567 tone decoder, tuned to the transceiver"s CW offset frequency, ensures that the transceiver will be tran
This oscillator-driver produces a deafening sound of about 3 kHz, modulated with a 10-Hz warble. BZ1 is a Matsushita EFB-RP3
Gasfet Frequency Doubler
This circuit will produce over +10 dBm in the 1800-3 000-MHz range. Drive power is 7 dBm in the 900-to-l 500-MHz r
Sawtooth Generator For Sweep Generators
This circuit will generate a linear sawtooth between 30 Hz and 3 000 Hz. Ql is a constant-current s
3.5 To 10Mhz Simple Superheterodyne Receiver
In this circuit, Ul is a frequency converter that feeds the 455-kHz IF stage U2 and detector
Reflex Radio Receiver
The RF signal is passed from the antenna through CI to the tuned circuit made up of LI and C2. One end of L2 feeds th
Hf Transceiver Mixer
The transceiver mixer and carrier oscillator in the band-imaging (7- and 14-MHz) CW transceiver. Careful selection of
Radio Commercial Zapper Circuit
The LR inputs are summed, dated and drive a comparator. The comparator senses level and generates a transition when audio inputs go above or below preset thresholds. The number of these transitions (corresponding to rapid volume changes) are integrated and feed voltage controlled amplifiers. This device actually senses dynamic range. BLOCK...
Conversion Receiver For 160 To 20M Circuit
Note that Tl and T2 are TOKO, including part numbers for the coils Tl and T2. The direct-con-version receiver shown uses a double-tuned input network made from readily available TOKO coils. IC1, an NE602, acts as a VFO and mixer, with the output being an IF frequency in the audio range.
Vlf Whistler Receiver Circuit
The VLF whistler receiver is intended to listen to natural radio noise and signals that occur below 20 kHz. LI is a large loop antenna that is 250 to 300 turns #26 gauge wire on a form 3` diameter.
FM Radio Circuits
RF Transmitter Circuits
RF Amplifier Circuits
AM Radio Circuits
FM Transmitter 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...
Digital Signal Integrity
Interconnection and Timing of Digital Circuits
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