Guide Information Blogs

This is a simple circuit but we hope it will help you a lot and save your valuable time. You do not have to use millimeter to test a transistor if you build this circuit. You can have a 9 volts battery to operate the circuit. No matter if the transistor is NPN or PNP, if the transistor is shorted then no any LED should light. If the transistor is open Both the LED should light.

Now remember when you test a good PNP transistor then LED2 should light.
For NPN good transistor only LED1 should light.

Try to make the circuit on a PCB and put in a small box for its safety. Find a three pin socket and mounted it on the box. When you fix everything, only visible parts from the out side of the box should be the switch and three pins of the socket to test a transistor.  

Suzuki Swift 1997 Electrical Wiring Diagram

defogger circuit, 1.3L engine performance circuit, horn circuit, instrument cluster circuit, interior light circuit, automatic transmission, power door lock circuit, radio circuits, power distribution circuit, shift interlock circuit, heater circuit, anti-lock brake circuits, Air back-up lamp circuit, exterior lamp circuit, warning system, wiper/washer circuit, ground distribution circuit, headlight circuit, conditioning circuit, charging circuit, starting circuit, supplemental restraint, etc. Features: assembly/dissasembly of the vehicle, to perform troubleshooting..

A pan pot enables a mono-phonic input signal to be positioned where desired between the stereo loudspeakers. When P1 (see diagram) is in the center position, there is no attenuation or amplification between the input and output. When the control is turned away from the center position, the signal in one channel will be amplified 3 dB more than the other. Circuit IC1 at the input is a buffer stage. It is arranged as an inverter to ensure that the phase of the input signal is identical to that of the output signal. The input impedance is set by R1 (10 kΩ). The output of the buffer is applied to stereo amplifiers IC2 and IC3. A special arrangement here is the positioning of P1, in conjunction with R3, R4, R8, and R9, in the feedback circuits of both amplifiers. This means that any adjustment of the potentiometer will have opposite effects in the amplifiers.

Series resistors R7 and R12 serve to ensure that the outputs can handle capacitive loads. Coupling capacitors C3, C6, and C9, may be omitted if an offset voltage of 20–30 mV is of no consequence in the relevant application. Capacitors C2, C5, and C8, ensure that the op amps remain stable even at unity gain. Capacitors C1, C4, and C7, minimize any r.f. interference, resulting in a usable bandwidth of 2.5 Hz to 200 kHz. The performance of the circuit is of sufficiently high quality to allow the pot being incorporated in good-quality control panels. Total harmonic distortion plus noise (THD+N) at a frequency of 1 kHz and a bandwidth of 22 kHz is 0.0014%. Over the band 20 Hz to 20 kHz and a bandwidth of 80 dB, this figure is still only 0.0023%. The circuit needs a power supply of ±18 V, from which it draws a current of about 16mA.

This broadband AM receiver enables you to ‘monitor’ the shortwave radio band. The circuit has been deliberately designed to have low selectivity and is most sensitive in the range from 6 to 20 MHz. This frequency range contains most of the shortwave broadcast stations. In this configuration, whichever station has the strongest signal will be the easiest to hear. An interesting fact is that the signal strength of stations in this band changes quite a lot. This is because the ionosphere reflects the radio signals. Because this layer of the atmosphere is in constant motion, the received signal strengths from different directions are subject to continuous variation. During testing of our prototype Radio Netherlands World Service, Radio Finland and Deutsche Welle alternated as the strongest station at regular intervals.


This receiver not only gives a good indication of the myriad of stations on offer in the short-wave band but is also an excellent tool for monitoring the state of the ionosphere. The circuit actually consists of no more than an RF and an AF amplifier. The high-frequency amplification is carried out by the IF stage of a CA3089. This IC is actually intended for FM receivers, but the FM section is not used here. The internal level detector provides a signal of sufficient strength to drive an audio amplifier directly. An LM386 was selected for this task. This IC can directly drive an 8-Ω loudspeaker or headphones without any difficulty.

The power supply voltage is 9 V. Because of the modest power consumption a 9-V battery is very suitable. In addition, the circuit will work down to a voltage of about 5.5 V, so that the battery life will be extra long. The antenna will require a little experimentation. We obtained reasonable results with a piece of wire 50 cm long. A length of wire in the range of 5 to 15 meters should provide even better results at these frequencies.

The crossover network is intended for use when an existing audio installation is to be extended by the addition of a subwoofer. Often, this additional loudspeaker is one that has been lying around for some time. If its frequency response extends down far enough, all is well and good, but a filter is then needed to cut off any frequencies above, say, 150 Hz. Often, a subwoofer network is an active filter, but here this would necessitate an additional power supply. The present network is a passive one, designed so that the speaker signal of the existing system can be used as the input signal.

Circuit diagram:

 Crossover Circuit Diagram For Subwoofer

Since the bass information is present in both (stereo) loudspeakers, the signal for the sub woofer can simply be tapped from one of them. The network is a 1st order low-pass filter with variable input (P1) and presettable cut-off frequency (P2). The signal from the loudspeaker is applied to terminal ‘LSP’. Voltage divider R1-R2-P1 is designed for use with the output signal of an average output amplifier of around d 50 W. The crossover frequency of the network may be varied between 50 Hz and 160 Hz with P2. The values of R3, P2, and C1, are calculated on the assumption that the subwoofer amplifier to be connected to K1 has a standard input resistance of 47 kΩ.

If this figure is lower, the value of C1 will need to be increased slightly. It is advisable to open the volume of the subwoofer amplifier fully and adjust the sound level with P1. This ensures that the input of the subwoofer amplifier cannot be overloaded or damaged. Make sure that the ground of the loudspeaker signal line is linked to the ground of the subwoofer amplifier. If phase reversal is required, this is best done by reversing the wires to the subwoofer. If notwithstanding the above additional protection is desired at the input of the subwoofer amplifier, this is best effected by ‘overload protection ’ elsewhere in this site.

Author: T. Giesberts Copyright: Elektor Electronics

Although not a new device, the LM317 is still a high-performance regulator. Its output voltage is essentially immune to fluctuations in load, supply voltage and temperature and this makes it ideal as the central element in a float charger for NiMH cells. Float charging has the advantage of keeping the cells fully charged and ready to use without the potential damage of long-term trickle charging or the cost of low-discharge cells. This works because NiMH cells do not have the memory problems associated with Ni-cads. The circuit is based on a conventional LM317 regulator. Resistors R2 & R3 and trimpot VR1 set the maximum output voltage to between 1.3V and 1.4V per cell. VR1 should be adjusted for a value of 1.35V per cell at the regulator output. Resistor R2 has been fixed at 240O. The formula for the voltage output is: Vout = 1.25*(1 + (R3 + VR1)/R2).
Diode D1 protects the circuit against reverse polarity of the power supply and protects the LM317 should the power be disconnected while it is still connected to a charged battery pack. Resistor RCL and transistor Q1 limit the maximum current in the event of a short circuit or the connection of a severely discharged battery pack. LED2 provides an indication of voltage input to the charger. LED1 and the 680O resistor provide the same function for the charger output and also provide a minimum load for the regulator when the battery pack is nearing full charge. This is necessary to keep the regulator output from drifting up and damaging the batteries. The circuit uses an external DC plugpack and is suitable for four NiMH cells rated at 2.5Ah.

Table 1 gives alternative values for 1-10 batteries in series at peak charge currents of between 200mA to 600mA. If you are using the specified plug-pack and the TO-220 packaged LM317T, you will need a heatsink rated at 12°C/W or better for any design other than the 200mA single cell charger. A TO-3 packaged device with the correct plug-pack will be OK without a heat-sink for any of the 200mA configurations and up to four cells charging at 400mA.