ICl is a 555 timer running at about 16 kHz. This IC drives Ql, a TIP146, which produces a 12-V square wave across Tl pri..
Put the car in reverse and the circuit provides a loud, audible beep at the rate of about one per second (1Hz). Half of U1, a 556 dual oscillator/timer, is used as a slow-pulse oscillator with a rate of about 1Hz. Components R2, R1, and C1 form the long time constant. You can calculate on time by t~.7 (R1 + R2) C1 or 1.15 seconds. The off time is shorter than the on time, at . 77 second. Enabling pin 4 (reset) is held high to keep the oscillator freerunning when voltage is.....
Using an oscillator running at 455 kHz, the metal-detector circuit produces an indication on the meter Ml. When the oscillat..
This tracking transmitter consists of four distinct subassemblies; a free-running multivibrator, a transmit switch, an audio-tone generator, and an FM transmitter. The multivibrator (which produces a pulse width with a pulse separation of 1500 ms) is built around Ql and Q2. The multivibrator output is coupled through R5 to the base of Q3, whose emitter feeds Q4, ..
The ignition substitute provides a constant power source for the ignition coil. Its frequency, 0.5-1.0 kHz, is that used by an 8-cylinder engine with an idling speed of 650 RPM, and the unit provides a rapid spark at a 17% duty cycle, while staying within the power dissipation limits of the components. The circuit consists of a 555 timer IC configured as an astable free~running multivibrator that is used to drive a high-current npn transistor, such as a 2N6384. The.....
The electronic darkroom timer is built around a 555 oscillator/timer, a pair of general-purpose transistors, a buzzer, and an LED. The 555 (Ul) is configured as an astable multivibrator (free-running oscillator). The frequency of the oscillator is determined by the values through i3 and Cl through C4. Switch SI is used to divide the capacitor network to vary the time interval between beeps; when SI is closed, the circuit beeps at intervals of 30 seconds. With SI closed,.....
This free-running TTL square-wave oscillator has a variable frequency output over a 20:1 range or better through use of four of the six inverters in an SN7404 chip and the additional components shown. Frequency of oscillation is determined by the capacitor and the settings of potentiometers R2 and R4; the first pot controls width Tl and the second controls width T2 of the square-wave output. ..
The 4047 is configured as a free-running, astable- multivibrator (oscillator) circuit. That configuration, offers three different outputs. The output pulses at the Q and Q output (pins 10 and 11, respectively) are the same as in the previous two circuits. The third output at pin 13 pulses twice as often as the outputs at 10 and 11. So, the circuit can be used to simultaneously provide both positive- and negative-trigger signals since the Q and Q output are never in.....
A simple 120 V: 24 V, center-tapped control transformer and four additional components can do the job. This circuit outputs a clean 200 V pk-pk square wave at 60 Hz and can supply up to 20 W. The circuit is self-starting and free-running. If Q1 is faster and has a higher gain than Q2, it will tum on first when you apply the input power and will hold Q2 off. Load current and transformer magnetizing current then flows in the upper half of the primary winding, and.....
This is the simplest of any programmable oscil lator circuit, since only one stable timing capacitor is required. The output square wave is about 25 V pk-pk, and bas rise and fall times of about 0.5 p,s. ..
This free-running multivibrator uses an external current sink to discharge the timing capacitor, C. Therefore, interval ^ may easily be 1000 the pulse duration, t1( which defines a positive output. Capacitor voltage, V^, is a negative going ramp with exponential rise during the pulse output periods. ..
This free-running square-wave oscillator uses two npn transistors. Output frequency is approximately 300 Hz ..
The threshold voltage, and thereby the time delay, of a free-running oscillator is shown modulated with a triangular-wave modulation signal..
That Circuit is an advanced bicycle lighting system which will power your lights and also charge four NiCd batteries while you running in the streets, for keeping the lights on while the bicycle is stoped. Its fully automated without any switches. ..
This waveshape generator is basically a slow running oscillator with variable attack and decay. A variable amplitude (high impedance) output is available via the 2M potentiometer. B shows an add-on circuit which should be used if a low impedance output is required..
A simple X-band radar detector is capable of indicating changes in rf radiation strength at levels down to 2 mW/cm2. Radiation falling on the detector diode, produces a voltage at the input of an amplifier whose gain may be adjusted to vary the range at which the warning is given. The amplifier output drives a voltage comparator with a variable threshold set to a level that avoids false alarms. The comparator output is connected in the wired-OR configuration with the open.....
Running a bath can end in a minor domestic disaster if you forget to turn off the taps in time. This indicator activ..
A low power, low cost dc lamp dimmer for a two-wire portable "flashlight" can be realized with little or no heatsinking. In addition, a single potentiometer, R3 adjusts lamp brightness. Battery power is stored in Cl for Ul, which is a free-running multivibrator whose frequency is determined by Rl, R2, R3, R4, and C2. ..
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 IC, which is used as a tuned rf amplifier. IC2, the LM565 PLL, is used as an FM demodulator. Pins 8 and 9 are connected to an.....
The automobile delayed kill switch is simple in concept. When you get out of your car, a secretly located pushbutton switch is pressed. Nothing apparently happens, but at the end of a predetermined time, a relay is pulled in and locked. When the relay is pulled in, contacts open, and the hot lead from the ignition to the coil and the hot wire from the key switch to the starter solenoid is opened or disconnected. If the engine is running, ..
Operational Amplifiers
Computer Systems
Oscilloscopes
Transmitters & Receivers
Sensors & Detectors
ANSI Standards
Low Frequency Amplifiers
Power Amplifiers
Number Systems
Regulated Power Supplies
Analogue Filters
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