The Internet caught the eye diagram of the automatic charger Ni-Cd batteries developed by Yuri Bashkatov. Assembled the circuit on the breadboard — not working. Modeled it on the computer using the program Work Bench. The result is what is shown in the diagram. The device operates as follows. The transistor VT1 (p-n-p) is open if at its base there is a negative potential, which may appear when the VT2 transistor (NPN) open — this, in turn, occurs if the potential at its base is installed with the variable resistor R4 will be 0.3 — 0.4 V higher than on its emitter.
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At first glance, the school gym is the same as thousands of others. But this is only at first glance… Observant person will note here something unusual. On boards and panels, attached to walls, installed button. Hanging above the light Board. The gym class begins with warm-up, and then the class is divided into groups. Students in one group with a small running start then jump at a time, hand hitting the button. While the scoreboard lights up every time the figure is estimation.
If during the day to measure the mains voltage, the voltmeter each time will be different. This is due to you can enable or disable individual power consumers, changing mode of operation (in accordance with the work schedule of production, process flow, etc.), that is, change the values of loads that cause instability of voltage in the networks.
Aquarists usually determine the turbidity of the water in the aquarium, visual manner (“eye”), and beginners don’t change it until then, until it is radiating the smell. However, with the help of an electronic device, which is easy to collect a couple of free evenings, you can control the suitability of water in the tank for future use, with high precision, eliminating the notorious “human factor”. Will benefit from this approach all people and their Pets in the aquarium.
In the Arsenal of the Amateur radio voltmeter almost the most important measuring device. But the trouble is that to produce and it is not always possible. And not because the scheme is complicated. For many, the stumbling block is the arrow microammeter. However, at first it can be replaced by electron-optical indicator 6Е5С (6Е1П) or neon lamp. But first you need a high anodic voltage (up to 300V), and the second measures relicina capacity below 55 V.
If you doubt the validity of a diode, transistor or want to determine their conductivity type, use one of the devices with which we introduce you in this article. The advantage of the devices is simplicity: they can even build a new ham. The basic design is based on schematics from the Bulgarian journal “Radio television electronics”.
Sometimes the output current in the power supply can be increased up to a critical value (due to the increase of power consumption, faulty connections or load devices), which will inevitably lead to the accident consequences of overload can be significant and even irreparable if you use a power supply without the security host (like today often make hams, making simple sources and buying cheap adapters) for Example will increase power consumption, can lead to failure of network transformer, it is possible to separate fire elements and odor.
The device is assembled on the proposed scheme allows to control the power consumed from the DC voltage source. Indication power led is a color display and sound. When using in-vehicle device control the power consumption of lighting devices and additional equipment replaces the voltmeter, connected in parallel with the battery.
The temperature of the soldering iron usually adjusted using Later. However, such devices are bulky, inconvenient for transportation. Significant benefits in this respect have electronic regulators. Thyristor controller — scheme presented in figure 1 — changes AC voltage at the electric soldering iron with power up to 50 watts 110 to 220 V.