Microcontroller to RS 485 circuit
| Microcontroller to RS-485 circuit diagrams |
Frequency to Voltage Converter Circuit
Simple Circuit 12V to 120V DC DC Converter
When pin 1 is high transistor Q1 conducts and current flows through the upper half of T1 primary winding. When pin 2 is the transistor Q2 conducts and high current flows through the lower half of the primary coil T1. As a result of a voltage of 120 V AC are induced in the secondary of T1. This voltage is rectified with bridge D1 to provide a 120V DC output. Capacitor C2 is the DC input filter, while C3, C4 are the output filters.
Notes.
- The circuit can be assembled on a vero board.
- Q1 and Q2 require heat sink.
- Output power of this dc dc converter is around 100 watts.
- IC1 and IC2 are to be mounted on holders.
- An optional 5A fuse can be added in series to the 12V supply line.
- T1 can be a 9-0-9V /250V/3A mains transformer.
- If 3A bridge is not available make one using 1N5408 diodes.
- Out of the two Flip-Flops inside CD4013 only one is used here.
- Output of IC1 must be set to 100Hz by adjusting preset R1
12 Volt Charger Circuit with LM350
Basic Principles of the LC resonance circuit
TDA 7309 Digital Audio Processor Circuit
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USB Battery Charger controller circuit using LM3622
TDA1308T Headphone amplifier circuit
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| TDA1308T Headphone amplifier circuit |
Traffic Lights Circuit
Well ... if youre looking for examples of a series of simple traffic light above the range can I recommend to you. The working principle of a series of traffic light above is very easy to understand. The series of above use the output from IC up / down counter 74 190 as the producer output tercacah and then conditioned using logic gates so that the logic in accordance with the logic of the actual traffic light. Actually you can also use the IC counter ups as pencacahnya. Red lights are represented by the LED D1, D2 and yellow by green led by led D3.
LIST OF COMPONENTS:
Resistors: R1 (1 Kohm), R2, R3 and R4 (220 ohms) and VR1 (Potensio 10 K / 15 K)
Capacitors: C1 (100 UF)
Led: D1 (red), D2 (yellow) and D3 (green).
Integrated Circuit: IC1 (NE 555), IC2 (74LS190) and IC3 (74LS02)
HOW TO WORK AND ANALYSIS OF CIRCUIT LIGHT TRAFFIC:
To generate the signal used peggerak counter circuit astable circuit IC555.
R1, C1 and VR1 is a combination astable as a determinant of the speed of the clock signal to be inserted to the input counter and in the end will determine the length of time the flame of their lamps. The greater the value of the three clock cycles will stay longer and vice versa.
To obtain a combination of LEDs required only 2 bits output from the counter circuit.
Bit-3 from the output to the counter only be used as reset the enumeration.
The lamp was first lit the light yellow color, due to connect with the output Q1 of counter IC. Then followed by a red lamp that is connected to the output Q2. Then both (yellow and red) light simultaneously. The last green light will turn on its own.
The series of bit counter counts up with the sequence:
- 0 1 (light yellow light)
- 1 0 (red light)
- 1 1 (light yellow and red lights)
- 0 0 (light turned green, according to the nature of the gate NOR)
Examples of traffic light sequence apply only to one lane for traffic light circuit that uses more than one line then you can use the same circuit device and use a combination of gates as a liaison between the conditions of each lane. This means you should make a longer red light is illuminated on each other point for point which it operates. These conditions can be achieved by utilizing a combination of logic gates in a chain.
50MW Audio Amplifier circuit
Due to recent increases in bias voltage between the emitter and base decreases as a result of minimizing driving. Input impedance is 500 ohms and the voltage gain is approximately five to eight ohm speaker connected. The voltage swing around the speaker is 2 volts without distorting production and capacity is at the same time in the 50 milliwatt range. A high voltage provided as well as the addition of heat sinks in the output transistors would be a great source of more power. Circuit thirty milliamperes draw a supply of 9 volts.
LED Flasher Circuit Using 555 Timer IC
FRIDGE DOOR ALARM CIRCUIT
Important Notes
- Delay time can be varied changing C1 and/or R3 values.
- Beeper repetition rate can be varied changing C2 and/or R4 values.
- Stand-by current drawing: 150µA.
- Place the circuit near the lamp and take it away when defrosting, to avoid circuit damage due to excessive moisture.
- Do not put this device in the freezer.
Circuit Diagram
Components List
GAS LEAK DETECTOR CIRCUIT
Circuit Schematic
SEN1327 gas sensor pin details
12v to 5v dc dc converter circuit diagram
Circuit Diagram of 12VDC to 5VDC converter:
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| Fig: 12 volt to 5 volt dc converter circuit schematic |
LA4440 Amplifier Circuit
Features of IC LA4440
- It has 46dB of ripple rejection
- Low distortion
- Good channel separation
- Thermal protector
- Overvoltage protector
- Surge voltage protector
LA4440 Stereo Amplifier Circuit
In the stereo amplifier configuration given below, C11 and C12 are output capacitor. But i ignore them from the circuit of bridge amplifier.
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| Fig-1: LA4440 Stereo Amplifier Circuit Diagram |
LA4440 Bridge Amplifier Circuit
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| Fig-2: LA4440 Bridge Amplifier Circuit Diagram |
Circuit description for both, stereo and bridge amplifier mode
CD4013 based Staircase switch circuit
If you really want to have classical staircase switch with push to switch on from one place and off from another place, here you have more circuits. Now you have two options to build the circuit here, one with light sensitive and another without it. Time delay is not incorporated here. We can use both facilities in a single IC or build them in separate ICs. Any or all of them can be used depending on the need.
Instead of ever present 555, this circuit now employs CD 4013 which has two D type latches in a single package. The circuit toggles a load with a momentary push button. Several push buttons can be fixed in parallel at various places to control the triac from any of those many locations. Two independent circuits can be made from a single IC. There are three options are here to show the flexibility of the idea and as a kind of tutorial for possible applications. Ideas from these circuits can be implemented in other similar circuits with due care.
A flip-flop is used to store or ‘lock’ one bit of information. This is known as ‘latching.’ Digital electronics and especially computers use a number of flip-flops, which latch several bits of data at the precise moment. There are a few variations of a classical flip flop i.e., JK, and RS. D type flip-flop is also one of them.
D-type flip-flop is just a clocked flip-flop with a single digital input D (D for Data). Every time a D-type flip-flop is clocked, its output follows whatever the state ofD is in. Intermediate state is avoided in this flip-flop. When the clock goes high, data at D (0 or 1) is transferred to Q. q will have the opposite of this state. When clock goes low, data remains unchanged. Q stores data until the clock goes high again when new data may be available.
CD4013 has two independent D type latches with set, reset, data and clock inputs. Both Q and are available as the outputs, which mean that both output states (high and low) or both toggle states are available. Set or reset is independent of clock.
TRUTH TABLE
| CLk | D | R | S | Q | Q- |
| low-hi | 0 | 0 | 0 | 0 | 1 |
| Low-hih | 1 | 0 | 0 | 1 | 0 |
| Hi- low | X | 0 | 0 | Q | Q |
| X | X | 1 | 0 | 0 | 1 |
| X | X | 0 | 1 | 1 | 0 |
| X | X | 1 | 1 | 1 | 1 |
No change
t = Level change Figure 30
x = Don’t care case
Now we have a series of circuits here using this IC. Circuit 1 and 2 are the same but the second circuit makes use of triacs. Third circuit has the option of light sensitivity incorporated in to it. Use of triac permits operation directly at mains. This IC has two D type latches and the description holds good for both. Hence it is possible to make two independent switches from the same IC.
The circuit is shown in Schematic As soon as the switch SI is pressed, clock input goes high and high data input is transferred to the output which drives a transistor, and hence forth a relay. Now q out put will be low and is coupled to data input now. At the next switch on of SI or S2, clock input goes high and data low. at D input is transferred to Qi transistor. Now Qj cannot any longer hold the relay up, and equipment switches off. Now Q Output is at high level, which is coupled to data input and the latch is ready for next sequence.
In general ICs do not like bad housekeeping, more so when handling mains voltages. Soldering is straightforward. A piece of Vero board is OK. CD4013 is a CMOS IC. Please respect it. Relays should be rated at the current required. Dl and D3 diodes are provided to protect the components from the back EMF generated by the relay coil. This is a standard method of relay circuit protection. Only two switches are shown as examples. You may add more number of switches for use at a number of different locations.
Latest In Circuit Transistor Checker Using 555 timer
10 000x With One Transistor Diagram Circuit
For simplicity, and assuming room temperature, we round this value to 40. For a single stage amplifier circuit with grounded emitter it holds that the gain Uout /Uin (for AC voltage) is in theory equal to SRc. As we observed before, the slope S is about 40Ic. From this follows that the gain is approximately equal to 40I cRc. What does this mean? In the first instance this leads to a very practical rule of thumb: that gain of a grounded emitter circuit amounts to 40·I c·Rc, which is equal to 40 times the voltage across the collector resistor.
If Ub is, for example, equal to 12 V and the collector is set to 5V, then we know, irrespective of the values of the resistors that the gain will be about 40R(12–5) = 280. Notable is the fact that in this way the gain can be very high in theory, by selecting a high power supply voltage. Such a voltage could be obtained from an isolating transformer from the mains. An isolating transformer can be made by connecting the secondaries of two transformers together, which results in a galvanically isolated mains voltage.Circuit diagram:
That means, that with a mains voltage of 240 Veff there will be about 340 V DC after rectification and filtering. If in the amplifier circuit the power supply voltage is now 340 V and the collector voltage is 2 V, then the gain is in theory equal to 40 x (340–2). This is more than 13,500 times! However, there are a few drawbacks in practice. This is related to the output characteristic of the transistor. In practice, it turns out that the transistor does actually have an output resistor between collector and emitter.
This output resistance exists as a transistor parameter and is called ‘hoe’. In normal designs this parameter is of no consequence because it has no noticeable effect if the collector resistor is not large. When powering the amplifier from 340 V and setting the collector current to 1 mA, the collector resistor will have a value of 338 k. Whether the ‘hoe’-parameter has any influence depends in the type of transistor. We also note that with such high gains, the base-collector capacitance in particular will start to play a role.
As a consequence the input frequency may not be too high. For a higher bandwidth we will have to use a transistor with small Cbc, such as a BF494 or perhaps even an SHF transistor such as a BFR91A. We will have to adjust the value of the base resistor to the new hfe. The author has carried out measurements with a BC547B at a power supply voltage of 30 V. A value of 2 V was chosen for the collector voltage. Measurements confirm the rule of thumb. The gain was more than 1,000 times and the effects of ‘hoe’ and the base-collector capacitance were not noticeable because of the now much smaller collector resistor.
Copyright: Elektor Electronics
PIC 16F88 based 4 digit Up Down counter circuit with explanation
This is a 4 digit decimal counter which can operate as a free running counter or in count and hold mode with manual reset. In either mode the counter can be preset to count to a specified value. Clock edge and leading zero suppression can also be configured. The 7-segment display and indicator LEDs are multiplexed. It will drive most common anode 7 segment LEDs. I used four single digit LEDs but a four digit LED module could also be used. In free running mode the overflow output resets on the next clock pulse. Therefore the pulse duration is directly related to the input clock frequency.
Read Source:http://picprojects.org.uk/projects/counter/counter.htm
USB Powered Wireless FM Transmitter Circuit FM Transmitter
Here’s a Wireless FM transmitter circuit powered from USB ports that could be used to play audio files on a standard VHF FM radio. The transmitter circuit use no coils that have to be wound. This FM transmitter can be used to listen to your own music throughout your home. When this FM transmitter used in the car, there is no need for a separate input to the car stereo to play back the music files from your MP3 player. This FM transmitter use a chip made by Maxim Integrated Products, the MAX2606 [1]. This IC from the MAX2605-MAX2609 series has been specifically designed for low-noise RF applications with a fixed frequency. The VCO (Voltage Controlled Oscillator) in this IC uses a Colpitts oscillator circuit. The variable-capacitance (varicap) diode and feedback capacitors for the tuning have also been integrated on this chip, so that you only need an external inductor to fix the central oscillator frequency.
It is possible to fine-tune the frequency by varying the voltage to the varicap. Not much is demanded of the inductor, a type with a relatively low Q factor (35 to 40) is sufficient according to Maxim. The supply voltage to the IC should be between 2.7 and 5.5 V, the current consumption is between 2 and 4 mA. With values like these it seemed a good idea to supply the circuit with power from a USB port.A common-mode choke is connected in series with the USB connections in order to avoid interference between the circuit and the PC supply. There is not much else to the circuit. The stereo signal connected to K1 is combined via R1 and R2 and is then passed via volume control P1 to the Tune input of IC1, where it causes the carrier wave to be frequency modulated. Filter R6/C7 is used to restrict the bandwidth of the audio signal. The setting of the frequency (across the whole VHF FM broadcast band) is done with P2, which is connected to the 5 V supply voltage.
The transmitter PCB designed uses resistors and capacitors with 0805 SMD packaging. The size of the board is only 41.2 x 17.9 mm, which is practically dongle-sized. For the aerial an almost straight copper track has been placed at the edge of the board. In practice we achieved a range of about 6 metres (18 feet) with this. There is also room for a 5-way SIL header on the board. Here we find the inputs to the 3.5 mm jack plug, the input to P1 and the supply voltage. The latter permits the circuit to be powered independently from the mains supply, via for example three AA batteries or a Lithium button cell. Inductor L1 in the prototype is a type made by Murata that has a fairly high Q factor: minimum 60 at 100 MHz.
P1 has the opposite effect to what you would expect (clockwise reduces the volume), because this made the board layout much easier. The deviation and audio bandwidth varies with the setting of P1. The maximum sensitivity of the audio input is fairly large. With P1 set to its maximum level, a stereo input of 10 mVrms is sufficient for the sound on the radio to remain clear. This also depends on the setting of the VCO. With a higher tuning voltage the input signal may be almost twice as large (see VCO tuning curve in the data sheet). Above that level some audible distortion becomes apparent. If the attenuation can’t be easily set by P1, you can increase the values of R1 and R2 without any problems.Measurements with an RF analyzer showed that the third harmonic had a strong presence in the transmitted spectrum (about 10 dB below the fundamental frequency). This should really have been much lower. With a low-impedance source connected to both inputs the bandwidth varies from 13.1 kHz (P1 at maximum) to 57 kHz (with the wiper of P1 set to 1/10).
In this circuit the pre-emphasis of the input is missing. Radios in Europe have a built-in de-emphasis network of 50 ?s (75 ?s in the US). The sound from the radio will therefore sound noticeably muffled. To correct this, and also to stop a stereo receiver from mistakenly reacting to a 19 kHz component in the audio signal, an enhancement circuit is published elsewhere in this issue (Pre-emphasis for FM Transmitter, also with a PCB). Author: Mathieu Coustans, Elektor Magazine, 2009
MP3 FM Transmitter Parts List
Resistors (all SMD 0805)
R1,R2 = 22k?
R3 = 4k?7
R4,R5 = 1k?
R6 = 270?
P1 = 10k? preset, SMD (TS53YJ103MR10 Vishay Sfernice, Farnell # 1557933)
P2 = 100k? preset, SMD(TS53YJ104MR10 Vishay Sfernice, Farnell # 1557934)
Capacitors (all SMD 0805)
C1,C2,C5 = 4?F7 10V
C3,C8 = 100nF
C4,C7 = 2nF2
C6 = 470nF
Inductors
L1 = 390nF, SMD 1206 (LQH31HNR39K03L Murata, Farnell # 1515418)
L2 = 2200? @ 100MHz, SMD, common-mode choke, 1206 type(DLW31SN222SQ2L Murata, Farnell #1515599)
Semiconductors
IC1 = MAX2606EUT+, SMD SOT23-6 (Maxim Integrated Products)
Miscellaneous
K1 = 3.5mm stereo audio jack SMD (SJ1-3513-SMT
CUI Inc, DIGI-Key # CP1-3513SJCT-ND)
K2 = 5-pin header (only required in combination with 090305-I pre-emphasis circuit)
K3 = USB connector type A, SMD (2410 07 Lumberg, Farnell # 1308875)
