Product Specification:
- Type: Operational Amplifier Test Board
- Material: PCB
- Size: Approx. 92 x 57 x 17mm / 3.62 x 2.24 x 0.67in
- Working Voltage: DC 12V
- Working Current: >100mA
Principle Introduction: The circuit features IC1a, connected to a multivibrator and an operational amplifier with a frequency of about 1Hz. The inverting input is connected to unity gain for testing purposes. IC2 is an EX OR gate, producing an output of 1 when the two inputs are inverted. So:
- If the op-amp is normal, points A and B of IC2 must be reversed, resulting in C being 1. This status is maintained after IC1b and 1d, causing the yellow LED D3 to light up.
- If the op-amp output is open, the C point of IC2 must remain 0. After passing through IC1c, it becomes 1, and the red LED D4 lights up.
- If the op-amp is internally shorted, resulting in a fixed positive or negative output voltage, the output of IC1c is a low-frequency square wave of 1Hz. The red and yellow LEDs will flash alternately.
For chips with lower slew rates, the LED always shows a yellow light, with a faint red flash, allowing a rough judgment of the chip's conversion rate. This can help in identifying counterfeit chips, as most second-hand chips on the market tend to have lower conversion rates.
Actual Test Results:
- Low Conversion Rate Chips (e.g., OP07, LM741): Yellow light always on, with a slight red light.
- High Conversion Rate Chips (e.g., TL071, NE5534, MC34071): Yellow light always on, red light off.
Compatible Op-Amp Models:
- Single Op-Amp: LM741, LF356, NE5534, TL071, TL081, OP07, and other standard package single op-amps.
- Dual Operational: LM358, NE5532, TL072, TL082, MC1458, RC4558, OP275, AD827, and other standard package dual operational amplifiers.
Package Includes: 1 x Operational Board
Note: This board is intended for use by individuals with professional electronic knowledge. It does not come with operational guidance or technical support. Beginners are advised not to purchase.
