There are still neighbors that keep annoying you by having loud the TV or the radio? Well I have you the solution. In fact all neighborhood will face your jamming waves at their TVs and radios, so be careful. This Jammer is the improved version of the old "TV and FM jammer schematic" with the difference of much higher power. Many of you where asking for a stronger and wider effect but to be as portable as can be. Looking at the schematic you can see that, only the.....
To generate regulated ± 5-V supplies from a pair of dry batteries, the circuit of Fig. 1 is commonly used. In order to give protection from inadvertent reverse connection of a battery, a diode in series with each battery would produce an unacceptable voltage drop. The more effective approach is to fit diodes Dl and D2 as shown in Fig. 2, in parallel with each battery. When the supply is switched off, there is the risk of a reverse bias being applied across the.....
Due to the low duty cycle of flashing LED, the average current drain is 1 mA or less. The NE555 will trigger the LED on when the monitored voltage falls to 12 volts..
This transmitter can be used for transmitter hunts, for remote key finding, or for radio telemetry in model rockets. It can be tuned to the two meter band or other VHF bands by charging Cl and Ll. 11 is four turns of #20 enameled wire airwound, 0.25 inch in diameter (use a drill bit), 0.2 inch long, centertapped. The antenna can be 18 inches of any type of wire. IC2 functions as an audio oscillator that is turned on and off by IC1 about once per second. ..
This field strength meter consists of a tuned crystal detector producing a dc output voltage from a transmitted signal. The dc voltage is used to shift the frequency of a transmitter of 100-mW power operating at 1650 kHz. The frequency shift is proportional to the received field strength...
The LM35 temperature sensor provides an output of 10 mV/C for every degree Celsius over 0C. At 20C the output voltage is 20 10 = 200 mV. The circuit consumes 00...
Precise, adjustable control of beats per minute from a largo of 18 to a frenzied, high presto of 500, These beats are produced acoustically through a speaker. A light flashes at the same rate. When SW1 is closed, CI begins to charge through Rl and R2. Cl will eventually reach a voltage at which the emitter of unijunction transistor is switched on, "dumping" the energy stored in Cl into an 8 ohm speaker. To produce a distinct "plop", brief pulses across T2 secondary drive.....
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 receiver dial corresponds to zero kHz; 3600 to 100 kHz; 3700 to 200 kHz, etc..
This unit is easily tunable and stable, consumes little power, and costs less than other types of oscillators tlmt operate at the same frequencies. This unusual combination of features is made possible by a design concept that includes operation of the transistor well beyond the 3 dB frequency of its currentversus- frequency curve. The concept takes advantage of newly available crystals that resonate at frequencies up to about 1 GHz. ..
A phase-controlled dimmer delays the triac turn-on to a selected point in each successive ac half cycle. Use this circuit only for incandescent lamps, heaters, soldering irons,..
This low-power video transmitter is useful for R/C applications, surveillance, or amateur radio applications. Seven transistors are used in a crystal oscillator-multiplier RF power amplifier chain, and a high-level video modulator. A 9- to 14-Vdc supply is required. ..
The step size of the converter is variable by selection of the high order data bits. The first DAC, A, has a stable reference current supplied via the 10.24 V reference IC and Rl. R2 provides bias cancellation. As shown, only the first 4 MSB inputs are used, giving a step size of 225/256 2.048/16 = 0.127 mA. This current supplies the reference for DAC whose step size is then 0.1275/256 = 0.498 µ. Complementary voltage outputs are available for unipolar output and.....
International Crystal OF-1 HI oscillator circuit for third-overtone crystals..
The circuit"s frequency of oscillation is/= 2.8/ [C1 x (R1 + R2)]. Using the values shown, the output frequency can be varied from 60 Hz to 20 kHz by rotating potentiometer R2. A portion of IC1"s output voltage is fed to its noninverting input at pin 3. The voltage serves as a reference for capacitor Cl, which is connected to the noninverting input at pin 2 of the IC. ..
A high-gain amplifier using a UA741 is used to sense relative voltage drop in a conductor, and therefore current i..
The rectifier input is tied to the input. This makes gain inversely proportional to input level so that a 20-dB drop in input level will produce a 20-dB increase in gain. The output will remain fixed at a constant level. The circuit will maintain an output level of 1 dB for an input range of +14 to -43 dB at 1 kHz...
Using the bilateral properties of a balanced mixer this transvertcr will produce 6-m output with 2-m inputs. Y1 is a 90-MHz crystal. Note that the input on 2 m is 143 to 144 MHz for 53 to 54-MHz output. This avoids possibility of extraneous 2-m reception during receive periods...
Used for digital control of musical instruments, this transmitter converts the digital data signals to equivalent optical signals for fiberoptic cable interface. Optocoupler IC1 provides isolation, and drives IC2-a and -b and Tl,..
In this circuit, audio fed to the control channel is amplified and rectified by Dl and D2. This dc level activates LED D3 via Q2. The light from D3 causes R9, a light-dependent resistor to decrease resistance. As Rll (audio gain) is set higher, more audio is present at the output of Ql. Audio fed into J2 is shunted to ground via R9 and less of this audio appears at J3...
The circuit consists of two basic circuits, the oscillator and the detector. The oscillator uses an FET in a Colpitts configuration. The energy circulating in the oscillator tank is coupled through C4 to the detector circuit, where a small diode (D2) rectifies it, feeding a dc voltage to the Darlington pair (Q2, A3) controlled by the sensitivity control (R3). Any small variations in the bias of the amplifier will cause large variations of current through the LED indicator.....
Operational Amplifiers
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