Keypad circuit schematic with 7611

This circuit is designed as a simple LED bar graph voltmeter. Each operational amplifier in the LM339 quad package functions as a comparator, comparing the input voltage (Vin) to a series of fixed voltage levels that are proportional to...

A simple level power meter designed to provide a high-fidelity sound system with a bar or dot matrix display. The green LED display indicates levels from 0 to 7; level 8 is shown in yellow, and level 9 is...

The non-contact lantern control circuit includes an integrated music IC (CIC2851), transistors (BG1 and BG2), a thyristor (SCR), and other components. When the switch is pressed (AN), the CIC2851 is activated, causing the output terminal (pin 3) to emit...

The Signetics NE5204 or NE5205 can be utilized in this audio frequency to 350-MHz (-30 dB) preamplifier. For a requirement of 600 MHz at 3 dB, the NE5205 should be employed. The noise figure is 4.8 dB at 75...

This circuit represents a negative resistance configuration. All previous circuits utilize RC time constants to achieve resonance. LC combinations can also be employed, providing good frequency stability, high Q factor, and rapid startup. In this circuit, a signal input...

A controllable gain amplifier functions as an automatic gain control circuit within the execution unit. The primary methods for controlling the amplifier's gain involve two approaches: one is by adjusting certain parameters of the amplifier itself, such as emitter...