Showing posts with label ic. Show all posts
Showing posts with label ic. Show all posts
Monday, October 20, 2014
Simle DC to AC Inverter by IC 555
This be basic AC inverter Circuit. Convenient for the initiator who have to is extremely fond of something experience. Because of use IC 555 highly popular, perform produce the frequency ,then enlarge with transistor NPN and PNP number TIP41 and TIP42 drive the coil transformer. Get by can pay Voltage output about 120V to 230V at frequency 50Hz. By have R4 perform control the frequency and should use. Voltage supply about 5V to 15V the detail sees in circuit picture sir. Link
Saturday, October 4, 2014
IC 555 based on water Activated Alarm
This water activated alarm circuit uses a NE555 timer wired as an astable oscillator and powered by the emitter current of transistor BC109C. In dry conditions, the transistor having no bias current and be completely off. As the probe gets wet, a small current flowing between the base and the emitter and the transistor turns on. A higher current flow in the collector circuit allows the IC NE555 osillator sound.
Probe / contacts may use a nonreactive metal. Contacts gold plated or silver age relay can be used, however, a cheaper alternative is the thread of alternate strips of copper a piece of veroboard. These will eventually oxidize over but as very little current flowing in the base circuit, the higher the impedance caused by oxidation is not important. No base resistor is necessary as the transistor is in emitter follower, current limit is the impedance at the emitter (the oscillator circuit)
Probe / contacts may use a nonreactive metal. Contacts gold plated or silver age relay can be used, however, a cheaper alternative is the thread of alternate strips of copper a piece of veroboard. These will eventually oxidize over but as very little current flowing in the base circuit, the higher the impedance caused by oxidation is not important. No base resistor is necessary as the transistor is in emitter follower, current limit is the impedance at the emitter (the oscillator circuit)
Thursday, October 2, 2014
Voltage and Frequency Calibrator Circuit Using IC 555
This circuit of a voltage and frequency calibrator provides simultaneous voltage and frequency calibrations by generation of a precision squarewave.
The 555 timer IC is used in a slightly unusual configuration, having the advantage that an exact 50:50 mark/space ratio may be attained by trimming R1. The frequency of oscillation may be set between l0 kHz and 1 kHz by switching timing capacitors C14. C5 decouples the internal ref- erence potential-divider of the 555 from supply·transients. The squarewave output from pin 3 of the IC, while stable in frequency, is not stable in peak-to-peak voltage as this depends on the supply voltage. This is used to switch on and off a temperature compensated constant- current source O1. R2 ensures that the current·source turns off completely when pin 3 goes high. The current- source output, trimmed by R3 to be exactly 1 mA, drives a resistor ladder network so that a series of precise squarewave voltages are generated. The advantage of current drive rather than voltage drive for this sort of net- work is that calibration is much easier. A simple ladder network is shown by way of example, and more complex ones may simply be constructed to give a wider variety of output voltages. The non-standard component values used were obtained by paralleling standard values. For the timing capacitors several in parallel had to be used, and only the resultant value is shown on the diagram.
The 555 timer IC is used in a slightly unusual configuration, having the advantage that an exact 50:50 mark/space ratio may be attained by trimming R1. The frequency of oscillation may be set between l0 kHz and 1 kHz by switching timing capacitors C14. C5 decouples the internal ref- erence potential-divider of the 555 from supply·transients. The squarewave output from pin 3 of the IC, while stable in frequency, is not stable in peak-to-peak voltage as this depends on the supply voltage. This is used to switch on and off a temperature compensated constant- current source O1. R2 ensures that the current·source turns off completely when pin 3 goes high. The current- source output, trimmed by R3 to be exactly 1 mA, drives a resistor ladder network so that a series of precise squarewave voltages are generated. The advantage of current drive rather than voltage drive for this sort of net- work is that calibration is much easier. A simple ladder network is shown by way of example, and more complex ones may simply be constructed to give a wider variety of output voltages. The non-standard component values used were obtained by paralleling standard values. For the timing capacitors several in parallel had to be used, and only the resultant value is shown on the diagram.
Simple IC 555 Touch Activated Switch Circuit
- An LED with a suitable series resistance may be included in the circuit and placed in the centre of the touch plate to indicate when the relay is activated. In cases of severe stray pick-up, the unit should be enclosed in a metal casing that should be grounded.
- In the circuit, some special precautions have been taken to avoid interference pick-up, to which TTL ICs are especially prone.
- To minimise stray pick-up, the interconnections should be as short as possible.
- Capacitor C2 is rather large compared to the conventional value (0.0lp.F) used in this position. This modification has proved quite effective.
- The power supply shown provides an appropriate DC voltage to drive a conventional relay.
- The value of Rl is best chosen by trail and error, and is a compromise between sensitivity and immunity from stray pick-up, Its value lies in the range l.8M to IOM. Rl may be excluded altogether.
- If the unitis situated away from the touch sensor, a shielded wire should be used for the connection.
- Tl acts as an inverter and converts a rising edge into a falling edge. Transistor T2 is used to provide sufficient drive capability to drive the relay. The external load is connected across the g relay contacts.
- An additional decoupling capacitor ((0.0lp.F) may be added as close as possible to the supply terminals of IC 7493. The prototype was constructed on a conventional bread- board.
- The circuit basically comprises a touch activated mono- stable vibrator using an NE555 IC, which activates the ITL s 7493 IC used as a bistable. , .
- Another modification is the addition of Cl-Rl parallel combination.
- The monostable is touch activated and it provides the triggering input to the bistable. However, the bistable triggers only on the falling edge of the monostable output pulse.
- This causes a time delay before the load is actually activated. To avoid this, Tl is introduced.
Saturday, September 13, 2014
Compressor Circuit with 570 571 Compandor IC
Compressor Circuit with 570/571 Compandor IC schema provide high gain for low amplitude input and provide low gain for high amplitude input. This action, in effect, produce a nearly constant amplitude even though the input has very high dynamic range (very high amplitude variation from time to time). The action of compression like this is needed in some situation, such as in maximizing modulation depth in broadcasting, or sustaining electric guitar signal which has very high variation between the plucking time and fading out. The following schema has complementary input/output characteristic and unity gain at 0.775 VRMS input. Voltage gain through compressor is square root of 0.7/Vin. Vin is average input voltage. This schema uses Signetics dual channel compandor IC. 570 has lower inherent distortion and higher supply voltage range (6-24 V) than 571 (6-18 V).
Compressor Circuit with 570/571
Tuesday, September 2, 2014
AF Power Amplifier IC with Thermal Shutdown
General Description:
Af powerr amplifier designed for a wide range of supply voltages to enable versatile application in entertainment electronics. The amplifier operates in tje push-pull B mode and is available in tje sip 9 package. The integrated shutdown protects the IC from overtheating.
Circuit diagram:
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| AF Power Amplifier IC with Thermal Shutdown |
Thursday, August 21, 2014
Build Intelligent Wire Loop Alarm Circuit With IC
Integrated schema anti-theft alarm system, wire or other lack of a simple schema. When the lack of wires or cords lacking. MOSFET, it is working or has input voltage at pin G and thus it has a high current flows through the pin D-S that Micro piezo siren was so loud.
Part List
R1 100K 1/2W 1% ResistorR2, R4 10K 1/2W 1% Resistor
R3 1 Meg 1/2W 1% Resistor
C1, C3 0.1uF Ceramic Disc Capacitor
C2 0.01uF Ceramic Disc Capacitor
IC1 4001UBE Quad 2-i/p NOR Gate
Q1 MPSA14 Low Power NPN Transistor
SIREN Micro piezo siren 12V DC 150mA, 110dB @ 1M
LOOP See “Notes”
The loop can be any type of hookup wire, with a maximum resistance of about 90K. Using very thin wire (40AWG, for example) will make a very sensitive trip wire, but will shorten the distance it can be strung due to the high resistance.
The siren can be replaced with a relay to drive external load
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